I'm having a problem with my PC loading. I have an HP a750y and run Win XP. I have plenty of memory. I have done all of the scans and do not get errors. My screen simply freezes in the middle of a program (any program) and then goes to sleep. I can not wake it up! I've tried everything. I have to hit the power button to turn it off. A while later I turn it back on and sometimes it loads fine, other times it just shows the message "going to sleep" and I'm back to square 1. I've reseated the video card, switched out the mouse, monitor and keyboard, changed the cables and electrical cords and boxes. Any ideas?