standby video problems?

Ok, I just built my computer. Minus a couple problems, this was one of the largest. My specs are as follows. Asus A7a 266fsb, 256ddr, geforce2ultra, Avitron 19" flatscreen trinitron. Ok, I leave my computer sit for a while and I come back to find my screen blanked out. when I turn it on I see a scrolling box with the text RGB with corresponding colors in it also. It says check video cable and something else below it. I exit that screen with a click and an error message pops up.. Com***.dll error. I close it and a new error acc*** error. Then explorer wants to close. After that it wants me to reinstall windows ME. This happens every time I leave my computer on for any large period of time. I believe it occurs after computer has been put on stand by or in suspend mode... What is the problem? Any suggestions?