I haven't touched a PC in years, so I haven't ever really had to worry about viruses and things like that. But a couple months ago, my browser was highjacked by something that kept redirecting me to a site called LinkBucks, which is just a page with a bunch of spammy links that pays referrers every time they send someone there. The worst part of it was, I'd google the issue, and then this virus (or whatever it was, I'm not sure it was a virus I guess) would block all virus scanning sites, and even support forums that described how to solve the problem!
It sounds like this is something a lot of other people are experiencing, so I figured I'd share how I've dealt with the problem. Without getting in to too much detail -- all you have to do to get rid of the re-direct is clear your browser cache, re-set your browser to default settings, and reset your ROUTER to factory settings. None of the virus scans ever found anything, because the virus lives in the router (apparently they can do that?!) so that's why you have to reset the router to factory settings.
One more note: if this problem is happening on one computer, don't connect any others to the wifi network until you've reset it! Otherwise they'll get it too. I made that mistake before I realized the router was the issue.