Ok, here's what's going on:
I'm using Windows 7 Home Premium 64bit edition. I use Mozilla Firefox 99% of the time. I've had McAfee Total Protection on my computer since July 2010, and as far as memory serves, this Google redirection problem occurred much later. I'll provide a detailed example:
I typed "Firefox automatically redirects" into the Google search bar, and this is what happens:
A list of results shows up, and I click on the top link. Goes right to the site. I hit the back button, choose the next link down, and again goes right to the site. I hit the back button again and choose the 3rd link, goes right to the site. I hit back a 4th time, and no matter which link I choose, I get redirected to a random ad site, some of which are listed as "malicious" by McAfee (big red X telling me the site is dangerous). I've also noticed that, when I click "Cached" instead of the actual link (from the Google search results page), I have no problems getting to the site I want to go to.
I've since downloaded Malwarebytes' Anti-Malware, Microsoft Security Essentials, Hitman Pro 3.5, and TFC.exe...I've run scans with all of them (and McAfee), and all have reported finding problems and all claimed to have taken care of them. I've run scans from all these programs since then, and all report everything hunky-dory. I've also tracked down some overlay.xul files in my and deleted them, and they came back. I tried deleting them and replacing with blank files, but a new overlay.xul was created in a new directory.
I'm still getting this incredibly annoying Google redirection problem.
I'd appreciate any help. Thank you in advance.