I've recently built a new system using these parts:
Antec quattro 850w PSU
MSI diamond mobo
BFG 8800gtx 768mb
3ghz core 2 duo
2gb corsair XMS ram
500gb Caviar sata hdd
I've had this system built for a couple of weeks now, and it has been great. I've kept an eye on the heat levels using speedfan and was happy to see that my cpu ran at 19 degrees idle, going up to around 25 under load. My gfx card however always ran at around 60-70 degrees, even idle but a quick google told me that is fairly normal for the 8800 range.
Tonight I loaded up the lord of the rings online and while I was still in the menu my computer made a loud pop and shut down.
Thinking this was maybe a power surge or I'd accidentally hit a button or something I turned it back on. At first I heard a grinding noise, then white smoke came out of the back in large amounts, and I could see what looked like fire through my side grilling.
I've turned it off since, and have looked around with a torch but I dont see anything burnt or anything, nor smoking. I grounded myself and put my finger on the cpu mount and its not even warm, nor is the cpu cooler, but the gfx card was still warm. All the fans seemed to be running but I dare not leave it on for more than a few seconds now for fear of a fire.
Any observations or suggestions as to where I should go from here would be greatly appreciated.