Chocolate Puppy :
I dont visit pr0n sites though. If I was the title would be "Help! Viruses!". That just makes me feel awful. :*(
Good that you don't, wasn't intended to make you feel awful. And the fact is, not all porn sites are littered with viruses, only the irresponsibly maintained ones. And even if you're sure your bro didn't surf them either, it's probably a good idea to do a sweep of scans with some of the more trusted, well known security tools to make sure that is not the problem, if you haven't already.
I use...
Avast AV
Comodo Firewall
CCleaner
Glary Utilities
HijackThis
Malwarebytes
First off, NEVER install an AV if you already have one on your PC. Uninstall the other first. Otherwise you can get problems, as they can conflict with one another. Avast is very good, the best free AV IMO. I have also used and prefer it to AVG, as Avast is better at catching viruses BEFORE they DL, is pretty good at stopping malicious ads, and does GMER's method of rootkit scanning on bootup. I used to use GMER as well, I don't need to anymore. Rootkits are used for identity theft, so it's good to scan for them.
All the above tools have free versions and all are easy to use. For Comodo to run without confusion though you need to install and activate ONLY the Firewall part of it via selecting Custom on the install screen, then opt out of Geek Buddy, Dragon, etc. After install, set it to Training mode (right click taskbar icon, enable Advanced view, Firewall, select Training mode. Also click HIPS, then select Training mode.
The only other tool that isn't pretty straight forward to use without a log analyzer is HijackThis, but you can simply go to http://www.hijackthis.de, paste in your log, and click analyze.