random reboots

hey i am sure that this is no surprise to many of you, but i wanted to share my experience with others because it took me 6 almost FULL days to fix! i was experiencing "random" reboots with a newly constructed PC. i was running 3 SATA drives, 2 CD-RW/DVD drives, an ATI X700 Pro vid card, P4 3.2, 2GB RAM on an Asus P5GD1 along with numerous fans and a "cheap" 550W PSU. the reboots would happen more consistently whilst playing several of the newer, graphic intense games (Doom 3, Half Life 2, Battle for Middle Earth, etc.) but, i would also experience these reboots while running any random program such as Windoctor or a malware checker, etc. well, i checked my memory, replaced the vid card, reinstalled windows (xp pro), ran diagnostics on my drivers and other hardware, and monitored my fan speeds, temps, and voltages via Asus probe (a utility included with Asus motherboards). My last try was replacing the PSU, and that did the trick! i did notice that there were small fluctuations in the voltages with the original PSU, but never went over 5% (BUT, may have went over that when playing games - i do not know because i turned the probe off when playing games). anyways i just thought i would share. DON'T BUY A CHEAP PSU !!