well, the type of shock I was getting was a constant shock. not like a
zap-ish static kind of shock.
as I said, it hasn't happened lately, but I have tried the PC in
different locations, and it did the same, so it shouldn't be anything
to do with ground. I even tried different power cables.
I assume it's either the dust and dirt, the case sucks, or a faulty
power supply.

unfortunately buying a new PC is out of the question at the moment,
financially. which is why I use an old junker for a media PC.
there aren't really any special devices hooked up to it. it's got a
video card, network card, and a USB infrared remote receiver. the
video card gets an s-video out, which is adapted to a composite, and
that hooks up to my tv. the audio is onboard, which also hooks up to
my tv.

I think what I'll try is cleaning it first, and letting it run for a
while. watch it constantly, and see if it's still doing it. if not,
success. if it does, I may try unsoldering the bypass capacitor.
if it's a faulty bypass capacitor, should I replace this part, solder
a bridge between the two leads, or simply leave it empty?