Hello Francis,
I'm sorry to hear about this. Please let us know where you have received that pop up (on your browser or on your desktop), that might be a false adware on your browser (no need to follow their pop up instruction to unlock the computer), also you can turn on your computer and run whole computer scan with AVG. If you have installed AVG Internet Security and it is active on computer then your computer is protected from all types of malware. If possible, please share a screenshot of that pop up. You can check the following link to see the instructions about taking the screenshot (http://support.avg.com/SupportArticleView?urlname=How-to-create-a-screenshot).
Best regards,
Alok.
I am got a pop-up that said my computer has been blocked. I have AVG ultimate. . I turn my computer off ASAP. Now what
Frances, If applicable… For your info, just in case that you are unaware, you can post the screenshot (http://avgclick.me/getscreenshot) here in your topic. Click on 'Answer' & then click on the 'Image' [mountain symbol] & follow the instructions.
AVG Guru