I looked up removal instructions on another computer, but they seemed too complicated for my extremely limited computer skills, so when I booted up in safe mode and Windows prompted me to ask if I wanted to use system restore, I decided to give it a shot.
I restored my system to the most recent save point (2 days ago) and voila, the problem seems to be solved. As far as I can tell, my computer is back to normal. I don't see the file that started the problem (I think psj was its name) in my program files anymore, and a McAfee scan found no infected files.
I'm worried that this was too easy. Is there something I'm missing? Is the virus still on my computer somewhere, and if so, what do I need to do to get rid of it permanently?