I have encountered this twice already, the last time looking for the game Solitaire.
This thread is *strictly* about a specific web page that says you have a virus, uses a synthetic voice, provides a phone number to call, and does not allow you to close the page no matter what you do. Even if you kill the browser and re-open it, it will once again re-open the page putting you back in the loop.
This is *NOT* malware, it's *NOT* a Trojan, it's *NOT* a virus, it's not anything except a cleverly crafted web page that uses javascript to prevent itself from being closed. That's all it is. thus finding a way to close the page and not re-open it clears up the problem because there is no actual virus on your computer.