Succession of hardware problems - ideas?

Hi

My brother in law's tower system (Acer Aspire 1641) went dead. Actually, when powered up, no display but got the normal one beep for all OK. Turned out the graphics card was dead. I removed it & plugged the monitor into the mobo graphics port. Screen OK.
Next, got as far as starting windows, hung there. No recovery disk or original media available. Could F8 though and got into a recovery screen. None of the options helped.
I decided the disk was screwed - either HW broken or windows corrupt or both.
I plugged in a different SATA drive and reinstalled Windows. All OK for several days.

Now (3 days later) he calls again. The damn PC is dead. Power on. Fans on. On/off light ON. NO other action. No screen, no beep etc. Tried removing ALL unnecessary HW (CDROM, memory, external devices, USB devices etc etc) Still the same.
PSU voltages read OK.
I think it's now the mobo BUT I also suspect that the PSU may be causing the damage given the amount of HW failure experienced in a few short days.

I suggested he salvage what he can, buy a refurb and ditch the old rig.

Any other suggestions? Thanks!

(Acer Aspire 1641, 3GB DDR2 mem, WD 500GB SATA drive, SATA DVD+RW, unknown mobo)

Try unplugging the computer, removing the cmos battery and holding the power button down.. if there are jumpers for the BIOS, short those out.. then reinstall the CMOS bottery and it should boot, at least once anyway.. I've seen this problem twice before and haven't been able to find a permanent fix for it. New memory, new graphics card, new PSU... nothing short of replacing the MOBO worked

That's the most expensive option, and it will work, but you'll be throwing away a lot of money on replacing perfectly good hardware

Thanks for replies...

Yep... tried the unplug / CMOS battery / hold down etc. No difference.

I tested the old HDD with a Hitachi diagnostic and it ran for ages then showed an error (honestly can't recall what...) which was when I swapped it & reinstalled.

So now I trust neither of the major remaining components - mobo / PSU - and believe that any further repairs are throwing good money after bad...

If resetting the CMOS didn't work, chances are it's just FUBAR anyway. Sometimes computers are lemons, just like with cars.