You can visually inspect for those on motherboard, video and other cards and in the power supply. The symptoms are consistent with this issue.
A friend of mine has a Compaq Presario SR2030NX Desktop. It is about 2 and a half years old. A lot of times when you turn it on, it sits there, no hard disk activity and nothing on the screen. I have tried diffrent monitors to no avail. Sometimes it boots, and there are no errors or BSOD's. I have also noticed that when installing updates recently that the screen had lines going across it, could it be the video card? NOTE: If you turn the computer off (after it does not boot up) and let it sit for about half an hour to an hour, it boots up fine. Please help me track down the culprit of this annoying problem.