A7N8X Deluxe won't POST unless at Default Settings

Hey all,

I've got a wee bit of a problem today. This morning when I tried to boot my desktop PC it wouldn't POST! (Computer specs at bottom of post)

After a quick CMOS clear, the PC posted fine. However, since then, ANY changes to the BIOS settings results in not posting. The system WILL BOOT and run fine if right after I clear the CMOS, go into BIOS with 'Del', navigate to the far right Screen (with the Exit options) and load the third option "Load Setup Options" (or something similar).

At this point, Windows will load, everything seems to work. Unfortunately my system is running severely underclocked (100 MHz FSB rather than the 166 it's supposed to be at). You can see in my Belarc Summary below that even though I've got an Athlon XP 3000+ in the system, it's identifying as a 1.3 Ghz processor rather than 2.2

With regards to when the computer doesn't post, I've got the Speech POST Reporter on, and instead of the POST screen I get no monitor signal and a "System Memory test failed" audio message.

If any of the BIOS settings are changed (even if I change the time, or turn off "POST Complete Notification") the system reverts to the Memory Test fail situation.

I've successfully flashed the BIOS to the newest version on the ASUS website (1008-D)

Memtest 3.1 (runs from Windows) ran through for about 40 minutes without an error, and I'm ready to run Memtest32 if necessary.

I did quite a bit of testing with the 2 RAM sticks, since I had removed them to test the RAM from another computer I'm trying to fix. Sticking them in singly in any of the 3 DIMM slots work at Setup configuration, but never with other settings. I also don't see how faulty RAM wouldn't work by turning off POST Voice Reporter.

Here's the specs:
OS: Windows XP Professional Service Pack 2 (build 2600)
System Model: ASUSTeK Computer INC. A7N8X2.0 REV 2.xx
Bus Clock: 100 megahertz
BIOS: Phoenix Technologies, LTD ASUS A7N8X2.0 Deluxe ACPI BIOS Rev 1008 08/04/2004

2 80GB Seagate Barracuda SATA Drives in RAID -0 config
1 LG DVD/CD-RW Drive
1 CD Drive
1 Floppy Drive
365 W Enermax PS
2 512 MB OCZ PC3200 Platinum Rev 2