blue screen of death

My Compaq Presario Desktop 7000 series with geforce 2 video card gives a blue screen when returning from sleep mode sometimes. At night, I turn off the monitor and leave it alone. When I turn on the monitor in the morning and move the mouse to getit out of sleep mode, a completely blue screen appears, with a gray rectangle at about the middle of the screen. There is absolutely no text. As I said I have a geforce 2 video card, Windows ME, and Norton Anti-Virus. I read that with Win XP the antivirus and video card combination could cause problems, so I post that information specifically. What can I do to fix this?