RFG PC crashing

[handra]

ii'm able to load the game ok but when its on the main menu it then freezes and crashes and brings up a error

the instrusction at "0x0087b4f0" referenced memory at "0x00000614" the memory could not be "read"

please help and i have updated the game via patch

well my pc is

* OS: Windows XP

* CPU: 2.70 GHzIntel Pentium Dual-Core E5400

* Memory: 3 GB RAM // 500GB with 330GB used

* Video Card: ZOTAC GeForce 8800GTS 1GB

BUT NOW crashes after 1 mission and only when i switch weapons why is this and what can i do to prevent this ?

and yes my motherboard grapghics card ect drivers are all upto date