Internet Worm/Trojan Help!?

The problem occured when my computer couldn't sign on to anything secure (eg. gmail, facebook, MSN messenger, bank account) two days ago. I did some research online and it turns out that Norton Internet Security caused a similar problem so I deleted mine and I could now sign on to all those. But now I need to replace my anti-virus so I downloaded AVG but it wouldn't install, neither would Hijackthis, Ccleaner, Avast, AntiVir and ZoneAlarm. Most errors are related to win32 not being an application or when I launch the ones that did install, nothing happens. Thus I can't run a virus scan but I did try Trend Micro and Ad-Aware (which is the only scanner working on my comp) but nothing picked up. I run WinXP Pro and I can't go into safemode - a blue screen shows up and it reboots itself. I need help big time, the more technical , the better! Thank you for reading

Internet Worm/Trojan Help!?antivirus downloads

This an online scanner that you dont have to download, just scan and remove the virus free,,

http://housecall.trendmicro.com/

SG

Internet Worm/Trojan Help!?cafe racer

Go too windows update and download all updates. If all else fails back up your documents and try a reformat.
The best way to get rid of trojans is using a best anti-spyware to protect your computer.Anti-Virus is not good at removing trojans,spywares and adwares.