I am working on an older Compaq which I determined to have a bad motherboard. I replaced it and finally got it to boot after reducing the amount of thermal compound I initially used. It ran for about 1 hour and I put it in standby. The next day it wouldn't respond at all. I unplugged it and that is the last boot I got. I am at my wits end with this. It will power up and the optic drive responds briefly but I get no post beep or video. I think I have a defective M/B. My question is: If I install a pci video card, does it bypass the gpu on the M/B? I did this to test and got the same results...Thanks for any help.