I've been working with, building, repairing and networking PC's for 25 years.
Can anyone recommend where to get the best deal on some sound proofing foam panels?
Thanks,
Mike
Man...if all you need is some foam fora PC iso-box...what's the big deal about finding a DEAL on foam???

I mean...you need just a few pieces, it's not going to cost all that much.
I thought you were originally looking to do an entire room.
The computer iso-box I built, I made out of 3/4" MDF board, and then I lined the inside of the box with some rubberized foam sheets...it's stuff they use on large HVAC ducts to kill some of the vibration noise. I drilled small air intake holes in the front door that line up the front of the PC tower intake slots...and then also large fan holes in the back that line up with the PC's exhaust fans.
It's NOT 100% soundproof, as there is some noise bleed out the fan portals, but it's about 75% quieter than if the PC tower was out in the open. Anything better than that will get very involved...or you might as well put the PC in another room like it's been suggested.
Normally I track to a tape deck, so th PC is not even on, but when I do tracking something really sensitive and go direct to PC, like say, a vocal...I'll temporally just drop a thick quilt over the whole iso-box, and it takes out another 10-15%...and really, it's good enough.