Sometimes, your computer may simply refuse to boot up. Maybe it gets past the POST (Power-On-Startup-Test – the beep you hear when you start up your computer) and then fails. Or, maybe nothing happens after you press the power button. Whatever the case, there are several different ways to fix this problem.
Double check all connections: Yes, you may have done this as the first step. However, even the most tech savvy PC users have been thwarted by a loose connector cord. Ensure that this isn’t the case by thoroughly checking and double checking every connection that goes to and from your PC.
Flip your PC onto its side: Sometimes, the problem is caused by a part that has become detached from the motherboard. If this is the case, then flipping your case onto its side could reconnect those parts. When your PC is vertical, gravity naturally tends to pull parts away from the motherboard. When it’s horizontal, gravity pushes your parts back towards the motherboard.
Check that the wall socket has power: If nothing happens when you hit the power button, then it may be a problem of your electrical system, not your computer. Check another device in the same wall socket as your computer in order to determine if this is the case.
Check for a motherboard problem: To see if your motherboard has failed, you must first eliminate every other problem. Detach every component from your motherboard except for the power, CPU, RAM, and graphics card, and then power it on. If it works, plug in your devices one by one to determine which one is causing the problem.
Check for a BIOS problem: The BIOS tells your motherboard how to run properly. It can also be a great place to look if your computer is failing immediately after startup. The moment your PC starts up, you will have to press a key like DEL, or F2 (the BIOS screen will indicate which button to press). Once you’re in, look for the ‘primary master’ setting, which should show your main hard drive. Not having a main hard drive connected would cause your PC to fail immediately. If there are numbers after this setting, then the BIOS has found your main drive.
Check for a bad hard drive: If there are no numbers after the primary master setting in the BIOS, then your hard drive may the issue. To make sure that it isn’t dead, try installing it into another computer. If it works, then it may be a cable problem with your old computer. Try switching out all the cables that are connecting to your hard drive.