OMG! that driver is like 3yrs old bro....
do yourself a favor and install the latest driver for your card at Nvidia.com
Pay attention on the uninstalling drivers instructions... BEFORE you start ;D
Make sure its a clean boot with as few as possible processes loaded and use a good defraging program.
#Special note: you do not mention your sound card/drivers, on such an old spec machine I would make sure that everything is updated... no matter its a card or onboard.
Read up at Tweakguides.com on BF2 settings
ADDED: are you 100% updated for XP?