FFXI - Blue Screen Partmgr.sys / atapi.sysFollow

Processor: Intel(R) Pentium(R) M processor 1.60GHz
33.7GB HDD 9.07 free
512MB RAM
ATI MOBILITY RADEON X300 (0x5460)
Windows XP

Lately, and this happened before, I play XI for a bit, then a blue screen comes up with...

A problem has been detected and windows has been shut down to prevent damage to your computer.

If this is the first time you've seen this Stop error screen, restart your computer. If this screen appears again, follow these steps:

Check to be sure you have adequate disk space. If a driver is identified in the Stop message, disable the driver or check with the manufacturer for driver updates. Try chaging video adapters.

Check with your hardware vendor for any BIOS updates. Disable BIOS memory options such as caching or shadowing. If you need to use Safe Mode to remove or disable components, restart your computer, press F8 to select Advanced Startup Options, and then select Safe Mode.

Technical Information:

STOP: 0x0000007E (0xC0000005 0xF84B638E 0xF8AB7C88, 0xFBAB7984)

sometimes with atapi.sys OR Partmgr.sys - Address F88EEFE3 base at F88EC000

The Partmgr.sys error is more common.

I must then pull the plug to restart my computer. This happened earlier in the year and I brought it into the shop, they mentioned something about it being the HDD or just files. I ended up wiping the whole thing clean and reinstalling windows and it worked wonderfully playing XI or otherwise for the last 6 months, no problems at all. However it's started happening again, and only when I start XI and play for about 5 minutes. I can run and boot all other programs with no trouble

Usually if I restart I'm OK, but if I try to keep playing multiple times, my computer won't boot to the windows loading screen claiming various errors, then I'm completely stuck. Additionally, the blue screen comes up when I DON'T try to start XI, like I've let the monster out of its cage. As long as I don't push the point by signing into XI everything seems fine, for now.

Any ideas?