I think most probably is the CPU itself cause problem, the heat. I build my Athlon TBird 1300MHz, with one seagate 10gb hd, 2-cdrom, SBLive!5.1, Keyspan Firewire card, 350watt PSU, Elsa Gladiac GTS, one fan suck in, two fans suck out. I use the Asus A7A Mobo. Everythings is OK after I change cpu fan to 7000rpm,wbk38. My temp is maintain at 52-58 degree. Last time i use the K-6, also hang due to the heat. A good ventilation in casing and high quality high speed fan definitely will help a lot. I use the WinXP proffesional edition