All was good, now all is lost

[Asrai]

We just finished assembling our build on Friday:

Aspire X-Discovery case
Asus A8N SLI Premium mobo
AMD Athlon 64 4600+
2 Maxtor 160g SATA drives (running RAID1)
2 Corsair Value Select 024 PC3200 DDR 400 MHz
NEC 16x dvd burner
Ultra 600w X-Finity power supply
Corsair Nautilus water cooling system
Creative Augity sound card
ATI X1900 512 video card
WinXP w/sp2 (brand new)

Got everything installed without a hitch, installed WinXP and the software for the video card and the sound card. Ran great Friday, installed my favorite MMO on Saturday and played all day without a hitch, no crashes, glitches, ect. Turned it on Sunday, went to play my game and my game crashed. Crashed a few more times then the computer started to reboot itself after each crash. I tried to reload Windows but I got error messages saying some of the files couldn't be loaded/are corrupt, but it installed anyway. Then it started to hang up when booting. Went into BIOS and I couldn't find my other drive listed anywhere and it's telling me I don't have another drive to do raid. Tried to get into Windows but that wouldn't load, so I disabled all of my raid settings. So now I have only one drive listed in BIOS and am stuck in a never-ending loop of either it hangs at the POST screen or it's stuck in a loop trying to install Windows. I need some serious help, as this is not my first build (2 of my others computers I built from scratch without a hitch) and I'm lost as to where to look or what to do.

[Panama Red]

Two things come to mind. One of the new hdd's failed which is causing the lack of recognition - try disconnecting one and test them with Maxtor's utility. Second, that Ultra brand psu has a distinct possibility of being flakey. One of the PC Mech staff tested Ultra psu's and it took 3 to find a good one. The voltages were all over the map on the first two. I'd replace it out of principle with a higher quality one.