GeForce2 mx400 32mb drops back to desktop

In 3dmark 200 ver. 1.1...it happens about 2 seconds into the 3rd test, the high detail helicopter. I took out my slow (128mb x 100 mhz) RAM stick, and left the 256mb x 133 stick in (in dimm 1), and cleared the bios, left everything at the default settings (except for setting the cpu back to 1.33, which is what it is)...my HSF isn't great, but it's very cool, tonight, heat shouldn't be the prob. 23c, right now, with vcool on, I tried running the tests with, and without, vcool, and RAMpage on. Nothing else running. Sandra says everything's fine. (I even tried 12 x 121fsb, and 11.5 x 125fsb, with the pci bus at 100mhz, and it seemed ok, until I ran 3dmark) Could it be the voltage? I don't have a setting above 1.85. This is frustrating. I've had all kindsa probs with this card (Giga-Byte brand, no fan, but it seems cool enough to the touch) Specs:

AMD Athlon 1.33
Abit KT7A, 4.33 4-in-ones, installed in 'normal', not turbo mode
Giga-Byte GeForce2 MX 400 32mb, ver. 12.41 drivers (I have the 21.83's, and I can get the 12.85's, but I figure it should at least finish the d***** test, with the 12.41's)
cheap Bestek sound card, in slot 4(C-Media 18738 chipset, tried board drivers, using chipset drivers)
Cnet pro200 nic card
LG 8080b cd-rw, manufacturor's drivers
generic floppy
H-P D7405B 15" monitor, from a pavilion, generic windoze drivers
300 watt power supply
256 mb Kingston ram, 133 mhz

I'm probably leavin a buncha stuff out, if anyone could please, please help me, I'll provide any other info ya need

I've had similar problems in the past. Some of the time, depending on what I was tweaking, it ended up being an overclocked video card, other times an overclocked CPU, and yet others interleaving memory or CAS settings. Something is halting your system when performing advanced mathematics. My first guess is a memory setting.

try to use a newer driver if you haven't... or you might want to reinstall windows or 3dmark without overclock.

It doesn't work at all, with the bios set anywhere but to the defaults (except for the cpu, I have to set that manually), I've read the GeForce faq's and Paul's Unofficial faq's for the kt7a...I tried to flash the video bios a while back, and inadvertently write-protected it, instead...is there a way to reverse this (I'm a DOS dummy,,,I can use format, fdisk, and cd, after that, things get iffy, lol)...I mean, it'll chug along, at 1.2, if I don't play anything more complex than civ2, (It's a 1.33), but this is getting frustrating. Oh, right now, I'm using win98se, with a 98lite 'sleek' install (95 shell)