Sinister Flaming Sinister

Maybe it's just a virus, but please help. I've ran my anti-virus - to no avail.

I have an asshole, who's an admin at some off-board, that has my ip and just won't let go. It's really ****ing stupid.

I start Windows, and during the setup, when it's thinking, my screen goes black for a couple seconds and then comes back on. Like it's loading something. Then I go to run a program, or play a game, and I get an indeterminate amount of time, then screen freeze. Hard restart the pc, again. I have two hard drives, both fresh Windows installs.