BSOD - Machine Check Exception

[OAB]

First- I did a seach of the forums, I found nothing of any help to my particular situation (though I'm bad at using non-google searching)

I have a computer, with an acomdata external firewire hard drive, and almost every time I do any kind of data transfer, while running multimedia tasks, on or off the drive, especially on the drive, the computer will BSOD with MACHINE_CHECK_EXCEPTION 0x000...09 (et all). I had this problem with a vantec enclosure, but it died several months back, and the Acomdata one was the replacement (a 'warranty' replacement), so it is not the enclosure.

Hardware:
AMD Athlon 64 X2 4200+ (no oc)
Abit AN8 Motherboard (vanilla nForce 4, latest drivers)
Crucial Ballistix 2-2-2-7-1 2x512mb (running at recommended voltage of 2.8)
ATI x1900 XTX graphics card (latest drivers 7.1, no 3rd party i.e. Omega/DNA, no OC)
Creative Soundblaster Audigy 2 ZS Platnim (latest drivers from creative auto-update, no "extra" creative tools)
Lite-ON WN5301A wireless (latest drivers via lite-on tech support)
Onboard sound - disabled
4x Samsung 160GB Hdds, RAID 0+1
1x Lite-ON DVD burner (SOHW-1693S, latest firmware)
1x Lite-ON CD-RW burner (SOHR-5238S, latest firmware)
Antec True-Power 550-II PSU
2x 80mm fans
1x 120mm fan for the hdd
Windows XP Pro (Retail/MSDN, SP2, all updates)

External hard drive: Acomdata USB/IEEE 1394 3.5" enclosure w/WD 250GB IDE drive in it, also had a Maxtor 200GB in it as well, same problem.

Basically, for a more detailed problem description, I cannot watch a movie using a firewire connection if the movie is stored on my external drive (DVD rips for example from my collection of legit dvds), I can with USB, perfectly, and even if I use the USB on this enclosure. I can transfer several gigs of files on or off the drive without problems, however, If I am watching DIVX video files (i.e. my home-made tv-rips of Mythbusters for example), I can if I don't jump around too much with teh seek bar, watch it perfectly off of the drive.

I cannot play podcats sometimes while I transfer songs to my iPod reliably without the computer crashing. The MS site gives no helpful information other then "it may be your pentium/pentium pro processor ..." and the wikipedia entry says it might be anything from mobo, to expansion cards, to RAM, to HDD) and the forum here said it may be a problem with my optical drives and my nvidia chipset conflicting.

What I have done to try and fix it:

Computer has passed memtest 86+ (looped overnight), PRIME 95 (two instances one per core), Hitachi/IBM HDD test (advanced, Samsung diags are POS), computer is generally otherwise stable. Passed chkdsk, ran defrag (perfect disk and windows, not that that ever fixes anything), ran SFC, ran spyware and adware scans (spybot/adaware), antivirus (Nod-32, latest defs as via the auto-update).

I HAVE re-installed the os (due to an unrelated incident and the resulting spyware).

I am (this particular re-install) using a custom-made install (via nLite) that removed OE and some of the stupid MS internet games, otherwise its default.

A couple of questions:
1- Is there anything I can do to fix this on my own and
2- Is there a problem with my soundcard, or is this just a design flaw in it?

I don't mean to tell my lifes story, but if there are any questions, you may ask.

 

[Hornswoggler]

I ran into this error the other day. From my searching and own troubleshooting, this is what I come up with:

- I hear the nvidia IDE drivers could be the cause. Could try uninstalling those and using native XP drivers?

- I removed all overclocking on the system in question and put the memory in single-channel mode. If it proves stable for a few weeks, i might gradually re-introduce the overclocks or dual chan.

- Could be overheating?

I know those are not conclusive suggestions, but I could not find any sure-fire cause or fix for this condition.