what happened to my system ? virus, rootkit or other ?

Hi, I just joined because I would like to learn what happened to my system. As it stands, it was (note past tense usage) xp pro sp3 system with NIS09 running.  Monday night I went to gameguru to see what was news there was pc games and tech stuff; IE 7- the window seemed to take too long downloading the page so I closed it and went to bed. Next day when I was clicking on a link while browsing an extra blank window opened. I found if I killed one window I could use that page. That was in the morning; by evening the ie basically froze if I navigated away from my home page (bbc)-the extra window opening was contrary to my preference to have windows open on the same page. I ran norton, ad aware, anti malwarebytes, hijack this- all found minor cookies etc but nothing fixed my problem. I found a rootkit detector program (rootrepeal) and ran that- it showed some interesting things, there were 4 hidden programs running that had the same prefix, but some odd font characters that made them stand out on the list. I googled those names and found nothing, which is very unusual as just about any file I find and type into google has a few corresponding entries- those were I suspected the source of my problems as it is my understanding that certain worms and virus have randomly generated names. I was unsucessful in trying to remove the rootkits and trying some things wound up with an unbootable operating system. Mild inconvience, everything on the disk was backed up. But I would still like to know what the heck infected my system ?