the joys of troubleshooting eh!
\l/..more stuff you probably already know: (im that bored)
The windows recovery console might help you repare it, if its a software problem (bootable from your xp cd)
(hardware is likely but its possible that after the format some software that caused the origional error has been reinstalled and has once again corrupted regestries or the like)
Tbh you need to find out what the bsod has to say for itself, before you run out and buy more expensive ram, sometimes they can indicate a range of possible issues, that might help you narrow it down.
good luck (and slap the next person you see buying ram modules with no static bag, that'll learn em

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