Acer laptop problem.

My roommate is having problems with his Acer laptop.

A Spysweeper virus alert popped up, saying that it automatically quarantined a trojan, which was followed by a Windows alert for the same trojan. After a slow response, he manually shut off the laptop.

Upon turning it back on and selecting "Start normally", the laptop blue-screened. He proceeded to turn it off again. He then was able to turn it back on and log in, only to have the same Windows alert pop-up and blue-screen him, again.

Now, the screen is black with writing on it. Notably, on the bottom, it reads:

"PXE-M0F: Exiting PXE ROM Operating system not found"

None of us are good with computers, so I'd thought I'd give this subreddit a shot. We appreciate any help given.