Did you connect the computer to the internet, without any firewalls or virus protection? That could be the cause of your problems.
I would post a Hijackthis Log in the Virus section of this forum, first, and see what advice you get from the people that can properly read the logs.
Intel E6750...........PSN: ELBATROP
XFX nForce 650i Ultra
Patriot PC2-6400 8GB (4x2GB)
36GB WD Raptor
Samsung SyncMaster 931c
Samsung SyncMaster 750s
Windows 7 Home Premium 64