GW locking up and crashing

I'm not entirely sure if this is my fault or something in guild wars, but I think a bit of both.

Quite a few times now I've been playing GW and for what seems like no obvious reason the game completely locks up, and in turn the entire computer locks up. I've not noticed any common themes with the crashing, its been in random locations doing random things.
Whats more bizarre though, after i've had to turn the comp off at the mains, it can then completely lock up whilst re-loading windows, either at the 'windows is starting up' message or the select user window. I've been told by a friend that it could be a memory problem, but as of yet i've not had time to run a complete 'memtest' at bootup. But since this is only happening when I play GW (not any other game) maybe someone here has come accross such a problem before and might have some advice

I'm currently playing on a pentium4 3.4ghz, 2gig DDR2 dual channel memory, geforce 7600gt (latest known drivers) and for in game settings 1024*768 with only the full screen gamma changing depending on which area it is.

If anyone could help clear light it'll be muchly appreciated

Have you checked the system logs to see if there is any kind of error logged when this happens?
At any rate, there are many possibilities...the best thing to do is to start testing things until you've narrowed things down to the culprit.

Possibilities:

• Bad memory module (running Memtest86+ = good advice)
• CPU or Northbridge overheating (this is easy to test...is it getting hot?)
• PSU not supplying constant power (test the PSU or try a different one)
• PSU not supplying enough power (upgraded something recently?)
• Unsteady power from the outlet (had any brown-outs, etc.?)
• Bad hard drive (bad sectors or dying logic components)
• Driver issues (if this is the case there will probably be something logged)
• Bad drive cable (not likely, but it happens and is oftentimes overlooked in troubleshooting)
• Jesus finds you distasteful

Does it always hang on bootup after GW has locked up? If you reboot after the startup hangs does it start up normally? Do you get the "Windows failed to start up on the last attempt yadda yadda yadda" after that happens?