Motherboard: CPU damage from power supply
The number one cause of bad motherboards and / or CPUs is a faulty power supply. Several years ago my home PC’s power supply literally caught fire. When the power supply went out, it took my motherboard and both hard drives. Needless to say, I lost a lot of data that I didn’t have a backup of.
When customers bring their PCs in for repair with the symptom “I press the power button and nothing happens”, it is very evident what happened. Whether it was some kind of power surge or internal failure with that PSU, it doesn’t matter, that PSU is toast. Now you need to find out if the damage is limited to the power supply or if it removed other key components as well.
First, change the power supply. The PC will get power and the fans will spin, but the motherboard POST? If not, you must first remove other components. If you have two memory cards, remove one card at the same time and try starting over. If it fails, reinstall the one you removed and then remove the next one. If startup still fails, remove both memory devices and install another device that was not on the PC originally. If that fails then you can remove the memory from being the problem.
The next thing you need to do is reset the CMOS to default settings. This can be achieved by using a reset jumper on the motherboard. The jumper should be located very close to the CMOS battery. The battery is the size of a quarter. Nearby, you should see three pins with a jumper on two of those pins. To reset CMOS, move the jumper over a slot. If you are having difficulty with this, an alternative method is to simply remove the battery for a minimum of half an hour. See your motherboard manual for exact instructions. If you don’t have the manual, you can find it online with a little research.
If the CMOS reset worked, GREAT! All you have to do is reset your watches and you should be in business. If it didn’t work, you can try unplugging your hard drive and see if the motherboard is posted. From experience this is a long shot, but you should try it first. If you’re still out of luck, then the motherboard, CPU, or both are bad.
Now, there is no sure way to determine which one is bad without replacing one of them. The dangers of this is that if you guess the CPU and it was the motherboard, when you replace the CPU with a new one, you will most likely damage the new CPU. Therefore, it is advisable to replace both of them. If you don’t, you could end up spending a lot more money than you originally planned.
Of course, now that you have changed the motherboard and CPU, all the hardware is working and you think you are out of the woods. PURPOSE, that is not the case. When you try to start Windows, 9 times out of 10, the operating system does not load due to the new motherboard. If you replaced the motherboard with the exact same model, you probably won’t have this problem. If you replaced the motherboard with a different model, you have two options:
1. Try to perform a repair installation of Windows. You will need the Windows disk to accomplish this.
2. If the above fails, you will have to reformat your hard drive, which means erasing the entire drive and doing a clean install of Windows.
If you have valuable data on your drive that is NOT backed up, you will have to start looking for ways to recover that data BEFORE reformatting.
Good luck!