A couple of weeks ago my AVG anti-virus alerted me that it had found a Trojan. This wasn't during its normal morning scan (where it has found problems before, but always fixed them), but actually at night while I was using the computer. The virus was "Trojan horse BackDoor.Generic11.ZNE" and I tried to use AVG to fix/heal/delete it. It told me the problem was fixed, but I kept getting the AVG pop-up telling me it was there. I also ran Malwarebytes and it said it had fixed all the issues it found (not sure if the Trojan was in the list of problems or not). The only problem it was causing was some google search redirects. Anyway, because AVG was still detecting it on scans, I tried using the Windows Live OneCare Safety Scanner ( http://onecare.live...._cid=mscom_msrt ) and it found some issues and "fixed" them. Since then, neither AVG or MalWarebytes finds the virus. Great, except that ever since that scan I've had issues with my computer freezing up. I don't know if the scan deleted a necessary file or what happened. Sometimes it freezes after a few minutes, sometimes it will stay on for an hour. I have noticed that playing a video or launching a web browser usually make it freeze up quicker than other uses. Strangely, it doesn't usually just freeze up completely (sometimes it does, though). Sometimes the video player will freeze (or the web browser will freeze), but I can still use other programs for a limited time. Sometimes it'll freeze and no programs will start, but I can still move the mouse around on the screen. Nothing I've tried can bring the PC back to working after it starts to freeze though- I have to just manually hit the reset button and let it reboot. So again, I'm not sure if this is still a Virus problem or if its moved on to a different problem.
Some system info:
Dell Inspiron 1520
Intel Core 2 Duo T7250 at 2.0Ghz
Windows XP Home SP3
Any help would be appreciated greatly, as it would be quite a hassle to have to format the hard drive and re-install windows.