If the screen is staying black it isn't just the mouse but something close to the vidcard or possibly the power supply. If you mean you get a black screen, then it boots on eventually it could be something more trivial. But your mouse is working fine during these times right? And the mouse not being detected wouldn't stop the system turning on.
My first system had symptoms like this and it turned out to be the old Banshee card wasn't connecting to the mobo properly. I'd open your CPU and tighten everything, check all cards etc.(not too tight btw) and make sure nothing is loose. Check for dust and do a standard cleaning.
__________________
Still I feel like a child when I look at the moon, maybe I grew up a little too soon...
|