[G4] G4 "Windtunnel" (AKA, MDD FW 800) Random crashes and other problems

[Nick Shank]

Hi all,
 I've spent almost 2 months messing w/ my G4. It's a Windtunnel DP 1.25, 
and has 4 1G sticks of DDR 333 from Crucial in it as RAM. Also, I have a 
pair of NEC 4X DVD-RW's, and 2 Seagate 120G HDD's. The video card is the 
stock Radeon 9000/64M, as well as a second Radeon 7000 PCI.
 Anywho, here's the problem. The thing randomly dies. After a clean 
load, with or w/o updates of 10.3, it runs fine for about 2 or 3 days, 
then dies. Then runs fine for about 2 hours, then dies, untill it takes 
about 3 days to boot again, only to die. I get errors from kernel traps 
(complaining about drivers for the machine) to the "You need to restart 
your computer" message, to just straight hard locks.
 I've tried the following: Pull the RAM, use the stock 256 that came w/ 
it. No joy. I've run memtest on the stock 256 that came w/ the machine 
on my P4. Let it run for about 2 weeks. No errors. Used the stock combo 
drive. No joy. Used the stock HDD (Seagate 80G). No joy. Droped the 
whole machine back to stock config. No Joy. Reset openrom back to 
defaults. No joy. Replaced the battery. No joy. Re-thermal compund the 
CPU's. Better, but I wasn't using it much that week anyway, so I 
wouldn't be so sure. I've even gone so far as to bench build the box, 
with a different powersupply. No joy.
 I do not have the original CD's that came w/ the machine. I did, 
however, buy a copy of tech tools pro 4.something, and, after 1 crash 
during the first run, it's ran perfect ever sence. Yes, I have tried on 
other loads. It only crashed the first time I ran it on that perticular 
load. Every other time, perfection.
 One thing I have noticed, however, is that when I tried to update the 
firmware (which I grabed from Apple's site, susposedly as the latest) I 
was told I have a version newer then the one I'm trying to install. Odd?!
 Other oddities: I can not install any other OS other then 10.3.2. 
_EVERYTHING_ else crashes,  refuses to install, or won't boot from 
installation media. I've tried a copy of 10.4, 10.2, 9, OpenBSD 3.5, 
Debian Stable, and I think NetBSD. Also, I read somewhere that this is 
caused from problems relating to the USB setup re: keyboard and mouse? 
Well, I have the original keyboard and mouse, as well as the now current 
apple keyboard and mouse.
 I'd really like to get this machine working again, but I fear I'm going 
to have to start replaceing parts, like CPU and mainboard, wich I'd 
rather not do, as that's about half way to a G5.
 Any help would be greatly appreciated, and anyone in the Seattle/Tacoma 
area who can help me get's free beer, or dinner, or both.
 Thanks
Nick