I've had my cab up and running for over a year and have been working on a random hang-up problem for that time as well. For reference, I'm running an Athlon XP 3000+ with 512Mb (or maybe 1Gb, I forget...I'll check) and an ATI 1300pro. The monitor is a 27" TV, so it adds a bit of heat and air flow restriction, but it's not the problem. I originally thought it was heat related, but after installing a pair of 80mm intake fans pointing at the open back of the case and installing a vent pipe to duct the heat away (via the psu), I still have crashes. I ran speedfan and recorded a log to see if anything was going on over time or just before the crash, but everything looks fine (cpu fan speed, all voltages, temp is a bit high, but level at 51C). I figured the only other thing it could be was bad ram, but I have been running MEMtest86 for 22 hours with 24 passed tests and 0 failures. Random crashes are usually heat, bad ram, or some type of memory hole (though less random). I've seen crashes in times as little as a couple hours or as much as overnight. I'm really just looking for suggestions of what to try. I was thinking a general system burn in test, but I can't seem to find a freeware/shareware one. Any thoughts?