OT: random locks/reboots

[Chris Zakelj <c_(_dot_)_zakelj_(_at_)_ieee_(_dot_)_org>]

Ok, this is way off for this list, but being the most technically saavy 
group I know, I'm hoping someone can shed some light on this (offlist, 
probably).  I recently did the following upgrades on my gaming machine:

CPU XP2100 (Palomino 266fsb) > XP3200 (Barton 400fsb)
GPU GeForce 4200Ti > GeForce 6800OC
RAM 1G PC2100 CAS 2.5 > 1G PC3200 CAS2.0
OS: Windows XP SP2 (I can hear the whoosh of a thousand torches being lit)

The motherboard is an FIC AU13, nForce2 chipset, so I know it's not a 
question of the motherboard not being able to support this stuff.  It 
got a CMOS clearing before the powerup as well.  The PSU is an Ultra 
500W.  The following comes off the BIOS PC-Health display:

CPU Temp 42C
System Temp 30C
Chip fan 2191 rpm
VCore 1.66v
* This is .015v below the BIOS setting of 1.675v.  I had to "warm" it 
up because the chip default of 1.65 gives VCore of 1.62
3.3v >   3.31v
+ 5v >   5.08v
+12v >  12.09v
-12v > -12.11v
- 5v > - 5.04v
VBat >   2.73v
5VSB >   5.01v

The temps are fine, and since all the rails are where they're supposed 
to be, I don't believe it's a PSU issue.  What does bug me is the 
battery... aren't they supposed to be 3V?  If so, could that be the 
reason for the problems?  Another interesting observation: It's sat here 
at the PC Health screen for nearly half a hour with no trouble, but 
Windows will lock or reboot within 5min every time, no errors, warnings, 
or log entries.  Ideas anybody?