2 hard drives not recognized

[zestril5]

Recently I was asked to fix a computer that indicated no hard drive. Bios in 3 different systems would not recognize the drive and the Maxtor diagnostics didn't find it either.
So I replaced the drive.The customer told me there had been a power surge so I explained to him that this was probably the cause. The case off/on switch on the computer was also a problem. Usually it had to be pushed 3 or 4 times before the system would come on. I suggested replacing the case since I don't get into fooling around with trying to locate things like off on switches but he declined.
At the same time as replacing the original drive a second drive was installed.
A week later I am called about the same problem on the same computer. This time the Power Supply is shot and neither hard drives are recognized in any system I put them in.
I tried different cables, different bios, different working systems and different power supplies but the hard drives are just not powering up.
I can fix the problem but as is often the case I can't explain what happened. Could a Power surge take out the 2 hard drives and power supply but not effect the CPU or Memory? I would really like to hear from others as to what they think could have caused this problem.
Thanks

 

[opalized]

A grey out, can and will cause havoc, the motherboard has onboard circuit breakers that will protect it in many cases.
the power supply should have been replaced after teh first harddrive faillure, with the current price of PS's, and the poor quality of the lower end units, its not worth the risk not to replace, unless its a high dollar supply, (antec)
if the harddrive diag software wont id them there gone.

 

[zestril5]

Thanks for the input Opalized.
This isn't the first time that I only suggested that something be replaced (in this case a tower with a sketchy off/on button and a power supply I knew had been through at least one major power surge)instead of just going ahead and replaceing it. And it's not the first time it's come back to bite me.
The customer isn't really appreciative that I tried to save them money especially when something more happens.
It won't happen again.