Today as I unplugged my USB graphics tablet, my computer immediatly lost power. After several attempts to restart it, I plugged the tablet back in, and it started again without me touching a single button or switch. A little freaked out, I decided not to touch the tablet until I had to.

Fast forwards a few hours later, when I was trying to insert another USB device. (my digital camera) As soon as the head of the USB touched the connector outlet, (it wasnt inserted at all) the computer suddenly lost power again. So far, all attempts to revive it a la the first time have failed.

My feeling is that that this is related to the PSU- could it be static electricity or some kind of power surge that happened as the metal made contact? It's quite mysterious to me.

Or perhaps it could the a bad motherboard?

Before I go out replacing parts and whatnot, Id like to get some second opinions and advice.

Thanks!

The most likely thing is the PS is failing and has fried the USB.

Failing power supplies are common and can cause your symptoms.
Check your PS.
See response 4 in this:
http://www.computing.net/hardware/w...

Try disabling the USB controllers in the bios. If the mboard is fine otherwise with those disabled, a PCI USB 2.0 controller card is cheap to buy and may work fine.
If not you will need another mboard.

"could it be static electricity or some kind of power surge that happened as the metal made contact?"

The metal shell - outside - of the USB ports are grounded, and so is the case, as long as the cord to the PS/case is properly grounded, so static electricity could not likely cause that as it would be drained away immediately. A power surge or spike as you were attempting to plug in a USB device could cause that if your computer isn't plupged into something that adequately protects EVERYTHING plugged into the computer from that (including your cable that connects you to the internet, and your phone line if applicable, and all devices that plug into AC), or a lightning strike anywhere on your power grid near you can get past such protection, but that's not likely - defective PSs often cause damage or symptoms that defy logic.
.....

Or there's a tiny possibility your mboard has the bad capacitor problem.

Open up your case and examine the mboard to see if you have bad capacitors, and/or other findable signs of mboard damage .

This was the original bad capacitor problem - has some example pictures.
History of why the exploding capacitors and which mboard makers were affected:
http://members.datafast.net.au/~dft...

What to look for, mboard symptoms, example pictures:
http://www.badcaps.net/pages.php?vid=5
Home page that site
- what the problem is caused by
- he says there are STILL bad capacitors on more recent mboards.
http://www.badcaps.net/

Pictures of blown capacitors, other components, power supplies, Athlon cpu's, etc.:
http://www.halfdone.com/Personal/Jo...

Are you using the same port/s that you have used sucessfully in the past?

my geuss is either power supply like mentioned above OR, one your usb prts not being grounded properly. It could be a fryed wire toughing medle and grounding out in your case or somthgin not being grounded. It could be a short soware, maybe as simple as a losse screw over your useb header pins. also were th usb "outlet" goes through the case it could be mounted improperly and causeing a short

Ultra Gladiator Blk Mid-Tower w/500w V-Series
Intel DP35DPM Socket 775 Motherboard
Intel Quad Core Kentsfield 2.4Ghz Q6600 CPU
Ultra 2048MB PC6400 DDR2 800MHz Dual Channel 2X1024
GeCub