From info I got, is that the computer was on left on the day we had a storm the power turned off and then on.
Power short somewhere I think, I have to hold the on button to keep the power going and when I do the fan doesn't run strong and makes some clicking noise. So does the hard drive.
I assume this is a desktop computer. I would start by replacing the power supply. You will need to remove every power cable before you remove the power supply. Then install the new power supply and reconnect the power cables.