大虾救命，电脑冻结

i even format my computer from fat to ntfs.
i installed windows xp service pack 2. When i go to internet, it still freeze.
i download trial version norton 2005 and updated it, scanned my computer. no virus found.
i tried macfee virus scan 2005 trial version, update it, scan it, no virus.
i tried microsoft anti-spyware, macfee anti-spyware, nothing found.
i tried tuneup 2004, can't solve the problem.
but when i installed macfee virusscan 7.1, it doesn't update, always failed.
Dachshund anticrash freeze itself.
Not working, still freeze (when i go to internet).
now i want to kill myself, help, help.....!!!!