Intel Duo 6300 1.8ghz
Nvidia 7800GT 256MB graphics card.
250GB Sata 7500rpm Hard drive.
It lags slightly when trying to play the demo of L4D2 even on lowish settings. I was just wondering which parts if any should be upgraded so that I could run games like L4D2 smoothly on about medium settings. If all the parts need to be upgraded which one should I upgrade first so that it's at least playable on low/medium settings without fps lag? I'd of thought it was my graphics card that is letting me down, but I could be wrong... Also if anyone has any recommendations of the hardware that would be upgradeable too, to suit my requirements, that would also be very useful.
Thank you for reading,