I assume you got the latest patches for the game right?
As far as your laptop (the hardware) goes, this laptop has been fitted with all the materials needed to run Vista and that's about it. Only 1 GB of memory and a 7900 GS videocard which is able to run Vista, but has serious issues running anything graphicly demanding next to it.
Even a older game like the first call of duty will have some serious issues on your config. Try finding a cheap 1 gb ram upgrade and it should solve your issues. Installing the latest videocard drivers might help too.
Drivers - Download NVIDIA Drivers
Also, do not resort to stupid things like turning of your firewall or anti virus to save a few megabytes of ram. Multiple websites promote that type of behaviour, but the risk simply isn't worth the trouble.
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