Critical component failures that won't let your computer boot are
Video Card (if not integrated)
Before going crazy troubleshooting, with the power off, check the CMOS battery to make sure it's still putting out 3V. If so, move the CMOS reset jumper to clear BIOS and return it to the normal position and attempt to restart. Dead backup batteries are a real issue after 3-5 years and are a cheap & easy fix.
Next, try removing all your memory and booting up. Your motherboard might beep at you (not all have the built in speakers for catastrophic failures, however. Sometimes the problem is caused by a loose connection in the memory or video card that has worked its way loose over time. Reseating the memory and video card is worth a try.
If you have a video card AND integrated graphics, try removing the video card and booting from the integrated graphics. That's about the only part you can easily pinpoint as the culprit.
Also - look at the motherboard's capacitors (the small plastic wrapped cans). If one or more of them is bulging, discolored, burnt or melted, that's a motherboard failure.
Good luck - tracking down the single point of failure without spare components to test against is a major undertaking.
· 7 years ago