I've had this happen on occasion with this forum. Likely a bad advertisement.
I've been in IT a looooong time. The biggest giveaway, more than the poor English, is the absolutely DIRE warnings. All the horrible things that could go wrong with your life, and your computer, if you don't immediately call the number below and grant them remote access to your computer. What they'll do is pull up event viewer, which even on a fully healthy computer will have warnings and errors. They'll use this as proof that there's problems with your computer, and they'll clean it for just $99. Or $199. Or whatever arbitrary amount they think they can get from you. So don't call. Don't click. Just Alt-F4 to close the browser. Run a virus scan, run a malware scan (Malwarebytes is nice), and you're fine.