Don't trust the site, especially if you get a popup telling you to go there when you shouldn't be getting such messages in the first place - it's likely whoever made that site has something to do with whatever infection you've got and they're trying to scam money from you, at the same time leaving you infected maybe with something else telling you to go to yet another site, and the process repeats

The scam must be catching a fair number of people though, for them to go to all this trouble

You'd be better waiting for your brother.
Antivirus scans isn't enough, you need to be doing spyware scans as well.
Best remedy in these cases is a reformat and reinstall of Windows anyway