someone help me about graphic card

[badass12]

hi this is badass , ihave a problem as when first time i play blc2007 it runs fine but after reboot i play it hangs or reboots the system automatically
as i have
AMD sempron
512 mb ram
NVIDIA geforce 6200 le 256mb card
windows xp

plzz someone help me about this problem its realy a headace!!!!!!!!!!1