This Computer Is Blocked POP-UP Scam
Written by Tomas Meskauskas on
(updated)
What is "This computer is blocked"?
"This computer is blocked" is a fake virus alert that occurs only when visiting an untrustworthy/deceptive website. Typically, users do not visit websites of this type intentionally - potentially unwanted applications (PUAs) redirect them to it.
As well as redirects to deceptive web pages, PUAs deliver ads and gather browsing-related (and other) data. Most infiltrate systems without users' consent.
As stated in the "This computer is blocked" pop-up window, the user's computer is blocked due to one of several reasons: the operating system registration key is illegal; the browser window is using pirated software or proliferateing viruses, or; it is hacked and being used from an undefined location.
According to the scammers, the computer is blocked for security reasons. The deceptive website itself gives the impression that it is legitimate and the virus alert comes from Microsoft Support. To prevent data damage or financial information tracking, users are urged to contact the 'support team' via the telephone number, "+1-855-552-7755".
Scammers use a number of identical websites that display fake virus alert messages, the only difference being the contact number provided (one example urges users to contact scammers via "+1-844-813-1513").
To make the scam even more believable, the malicious website starts automatically downloading random files (which are harmless) to make the browser crash. Typically, cyber criminals who these fake virus alerts claim to be representatives of the operating system's support team (depending on the operating system).
In this case, they attempt to give the impression that they are Microsoft support team members. Note that Microsoft has nothing to do with this. Scammers attempt to give the impression that there is a problem with the system (the computer is infected, damaged, and so on) and try to trick people into contacting them via the telephone numbers.
The main purpose is to trick users into paying for software or technical services that, according to these cyber criminals, will fix the problem (remove viruses, etc). We strongly recommend that you ignore fake virus alert messages (or other similar messages) of this type.
Simply close the opened window and never return to the site. If the website prevents you from closing it, close the entire browser or terminate the browser process using Task Manager. Do not restore the closed session the next time you open your browser - this will lead you to a deceptive website (or the website that led you to this dubious site in the first place).
PUAs that cause redirects to deceptive websites also deliver intrusive ads and gather data. These apps feed users with pop-ups, surveys, coupons, banners, and other similar intrusive ads. Furthermore, the ads are usually displayed through tools that enable placement of third party graphical content on any site.
They conceal underlying content of any visited website. If clicked, they redirect users to untrustworthy and potentially malicious websites or execute scripts designed to download/install other unwanted apps.
Another downside of potentially unwanted apps is that most record browsing-related data such as IP addresses, keystrokes, search queries, URLs of visited websites, and so on. They often target personal/sensitive data. PUA developers share this private data with third parties (potentially, cyber criminals) who misuse it to generate revenue.
If installed, these apps might cause various privacy, browsing safety issues, or even identity theft. We strongly recommend that you uninstall PUAs immediately.
| Name | "This computer is blocked" virus |
| Threat Type | Phishing, Scam, Social Engineering, Fraud |
| Symptoms | Unauthorized online purchases, changed online account passwords, identity theft, illegal access of one's computer. |
| Distribution methods | Deceptive emails, rogue online pop-up ads, search engine poisoning techniques, misspelled domains. |
| Damage | Loss of sensitive private information, monetary loss, identity theft. |
| Malware Removal (Windows) | To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. |
Many websites are designed to display fake virus and other messages. Some examples are MS MALWARE ALERT, Your Computer Was Locked, and Error # 0xx90025ee9. Despite the differences, most deceptive websites displaying fake messages are used to trick people into purchasing unnecessary software or online technical services.
Unwanted apps that lead to these websites are mostly similar and share the same purpose: to generate revenue by collecting data, causing unwanted redirects, and feeding users with ads. Developers promote them as 'useful apps', but these are merely attempts to trick people into downloading and installing rogue software.
These apps cause problems relating to privacy and browsing safety.
How did potentially unwanted applications install on my computer?
Some potentially unwanted apps have official websites from which they can be downloaded, however, most users install them through intrusive (untrustworthy) ads or when software developers use "bundling", a deceptive marketing method used to trick people into installing unwanted programs together with regular software (usually free).
Developers hide PUAs in "Custom", "Advanced", "Manual" and other similar settings/options of the download/installation set-ups - they do not disclose information regarding these installations properly. Furthermore, many users skip installation steps when installing software, thus leading to installation of additional PUAs.
How to avoid installation of potentially unwanted applications?
Avoid using third party software downloaders/installers or untrustworthy websites to download software. Use official, trustworthy websites, and direct links only. Check "Custom", "Advanced" and other similar settings/options, during any installation. Opt-out of unwanted offers, features, extras, and so on.
Only then finish the installation. Be careful when browsing the web and avoid clicking intrusive ads, even if they seem legitimate. Some redirect to dubious (potentially malicious) websites such as pornography, adult dating, gambling, etc.
If you encounter these intrusive ads (or redirects caused by them), check installed programs on your computer and extensions, add-ons, and plug-ins installed on your browser. If you find any unwanted/suspicious entries, eliminate them immediately.
If your computer is already infected with PUAs, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate them.
Text presented in the "This computer is blocked" scam pop-up:
VIRUS ALERT FROM MICROSOFT
This computer is BLOCKED
Do not close this windows and restart your computer
Your computer's registration key is Blocked.
Why we blocked your computer?
The window's registration key is illegal.
This window is using pirated software.
this window is sending virus over the Internet.
This window is hacked or used from undefined location.
We block this computer for your security
Contact microsoft helpline to reactivate your computer.
Text presented in the "This computer is blocked" red background:
Windows Support Alert
Your System Detected Some Unusual Activity
It might harm your computer data and track your financial activities
Please report this activity to +1-855-552-7755
[Ignore Alert] [Chat Now]
The appearance of "This computer is blocked" pop-up (GIF):
Another variant of "This computer is blocked" pop-up (criminals use the "+1-844-813-1513" telephone number) :
The appearance of this variant (GIF):
Another variant of this scam (crooks use "+1-877-211-5018" telephone number and the error text is virtually the same):
Screenshot of the website:
Appearance of the website (GIF):
Appearance of a German "This Computer Is Blocked" pop-up scam variant:
Text presented within:
Dieser Computer ist blockiert
Rufen Sie jetzt die Hotline an 0800-180-1054 (gebührenfrei)
[Zurück sur Sicherheit] [Jetzt aussteigen]
Instant automatic malware removal:
Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
▼ DOWNLOAD Combo Cleaner
By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.
Quick menu:
- What is This computer is blocked?
- STEP 1. Uninstall deceptive applications using Control Panel.
- STEP 2. Remove adware from Internet Explorer.
- STEP 3. Remove rogue extensions from Google Chrome.
- STEP 4. Remove potentially unwanted plug-ins from Mozilla Firefox.
- STEP 5. Remove rogue extensions from Safari.
- STEP 6. Remove rogue plug-ins from Microsoft Edge.
Removal of potentially unwanted applications:
Windows 11 users:
Right-click on the Start icon, select Apps and Features. In the opened window search for the application you want to uninstall, after locating it, click on the three vertical dots and select Uninstall.
Windows 10 users:
Right-click in the lower left corner of the screen, in the Quick Access Menu select Control Panel. In the opened window choose Programs and Features.
Windows 7 users:
Click Start (Windows Logo at the bottom left corner of your desktop), choose Control Panel. Locate Programs and click Uninstall a program.
macOS (OSX) users:
Click Finder, in the opened screen select Applications. Drag the app from the Applications folder to the Trash (located in your Dock), then right click the Trash icon and select Empty Trash.
In the uninstall programs window, look for any suspicious/recently-installed applications, select these entries and click "Uninstall" or "Remove".
After uninstalling the potentially unwanted application, scan your computer for any remaining unwanted components or possible malware infections. To scan your computer, use recommended malware removal software.
Remove rogue extensions from Internet browsers:
Video showing how to remove potentially unwanted browser add-ons:
Remove malicious add-ons from Internet Explorer:
Click the "gear" icon 
(at the top right corner of Internet Explorer), select "Manage Add-ons". Look for any recently-installed suspicious browser extensions, select these entries and click "Remove".
Optional method:
If you continue to have problems with removal of the "this computer is blocked" virus, reset your Internet Explorer settings to default.
Windows XP users: Click Start, click Run, in the opened window type inetcpl.cpl In the opened window click the Advanced tab, then click Reset.
Windows Vista and Windows 7 users: Click the Windows logo, in the start search box type inetcpl.cpl and click enter. In the opened window click the Advanced tab, then click Reset.
Windows 8 users: Open Internet Explorer and click the gear icon. Select Internet Options.
In the opened window, select the Advanced tab.
Click the Reset button.
Confirm that you wish to reset Internet Explorer settings to default by clicking the Reset button.
Remove malicious extensions from Google Chrome:
Click the Chrome menu icon 
(at the top right corner of Google Chrome), select "More tools" and click "Extensions". Locate all recently-installed suspicious browser add-ons and remove them.
Optional method:
If you continue to have problems with removal of the "this computer is blocked" virus, reset your Google Chrome browser settings. Click the Chrome menu icon (at the top right corner of Google Chrome) and select Settings. Scroll down to the bottom of the screen. Click the Advanced… link.
After scrolling to the bottom of the screen, click the Reset (Restore settings to their original defaults) button.
In the opened window, confirm that you wish to reset Google Chrome settings to default by clicking the Reset button.
Remove malicious plug-ins from Mozilla Firefox:
Click the Firefox menu 
(at the top right corner of the main window), select "Add-ons". Click on "Extensions", in the opened window, remove all recently-installed suspicious browser plug-ins.
Optional method:
Computer users who have problems with "this computer is blocked" virus removal can reset their Mozilla Firefox settings.
Open Mozilla Firefox, at the top right corner of the main window, click the Firefox menu, in the opened menu, click Help.
Select Troubleshooting Information.
In the opened window, click the Refresh Firefox button.
In the opened window, confirm that you wish to reset Mozilla Firefox settings to default by clicking the Refresh Firefox button.
Remove malicious extensions from Safari:
Make sure your Safari browser is active, click Safari menu, and select Preferences....
In the opened window click Extensions, locate any recently installed suspicious extension, select it and click Uninstall.
Optional method:
Make sure your Safari browser is active and click on Safari menu. From the drop down menu select Clear History and Website Data...
In the opened window select all history and click the Clear History button.
Remove malicious extensions from Microsoft Edge:
Click the Edge menu icon 
(at the upper-right corner of Microsoft Edge), select "Extensions". Locate all recently-installed suspicious browser add-ons and click "Remove" below their names.
Optional method:
If you continue to have problems with removal of the "this computer is blocked" virus, reset your Microsoft Edge browser settings. Click the Edge menu icon (at the top right corner of Microsoft Edge) and select Settings.
In the opened settings menu select Reset settings.
Select Restore settings to their default values. In the opened window, confirm that you wish to reset Microsoft Edge settings to default by clicking the Reset button.
- If this did not help, follow these alternative instructions explaining how to reset the Microsoft Edge browser.
Summary:
Commonly, adware or potentially unwanted applications infiltrate Internet browsers through free software downloads. Note that the safest source for downloading free software is via developers' websites only. To avoid installation of adware, be very attentive when downloading and installing free software. When installing previously-downloaded free programs, choose the custom or advanced installation options – this step will reveal any potentially unwanted applications listed for installation together with your chosen free program.
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Outstanding!
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