Counter Strike - on a laptop - lag issues

Hi everyone,
I just got a Dell Latittude D610 laptop and loaded Counter Strike on it. I'm experiencing a lot of lag in all maps except one in the game. Does anyone have any ideas how to correct this if possible? Some other games I've loaded are StarCraft and WarCraft and they run just fine.
Thanks so much!

As you have a Radeon Mobility X300 in your laptop.
I sugggest you dont use higher resosloution, than 1024 X 768, 16 bit colour And let the quality settings be at "program controlled" and low inside the game.

Later on, If I where you. I would examine the possibilitys, to replace the mobility X300, with a mobility x800 for ex. But monting a new videocard into the laptop, is a job for a service station. Preferable a Dell station.

If you have 512mb of RAM? Then get another 512mb stick. This a s the minimum requirement for RAM, using Windows xp is 512mb

what kind of lag are u recieiving??it can be network connections and rates. type this in console net_graph 3 by pressing ` under the esc in counterstrike. You will then see your latency as in ms and fps "frame rate persecond". Most custom maps makes your fps drop while in game. also type in max_fps 100 or fps_max 100 one of them is correct.