> my 9yo daughter looks shocked and says the computer buzzed her.  i touch what she touched, floor grate and computer chassis, and buzzo.  so perhaps improper grounding might be a factor in mobo deaths?  


Many years ago, I got a shock from the metal chassis of my dad's reel-to-reel tape deck.  He said "unplug and plug it in the other way" (this was before the days polarized plugs).  I tried this and it worked!  

The explanation was that there was a high-impedance short between the power transformer and the chassis.  Plugging it in the other way moved the short closer to neutral (grounded at the fuse-box and the utility pole).

Assuming you have a polarized plug, you might check your outlet.  You can buy a 3-led tester at the hardware store for less than $5.

If you're using a UPS, then that may be at fault.