Spec issue.

[xaxpop]

Hi guys, im having MAJOR lag when i try to play PR, drops bellow 15fps almost always making it impossible to play, this even occurs when i tryied putting textures to LOW!

My specs are:
Geforce 8600M GT 256 mb
, 2,2 Ghz Intel Core 2 Duo T7500,
2gb DDR2 ram.
Windows Vista

Of course its not nearly the best but isnt it enough to play PR? :S
Might need a reinstall of the system since its been used a while and that might be the problem,
what do you guys think this system can run PR ?