You can download and install the Nvidia GPU (Graphics Processing Unit) drivers from www.nvidia.com and following the 'Drivers' link at the top of the screen. The website will offer you a range of options to determine the correct drivers to download and install. Once downloaded, install the drivers in the same manner as you would any other windows program.
I would recommend you do not delete the Integrated Graphics Chipset drivers your motherboard is using. Under functional circumstances, when your computer is using your Graphics Card and not the Integrated Graphics Chipset, these drivers will not interfere with any performance aspect of your games.
To address your first post: If your Nvidia Drivers aren't installed your PC will not use your Graphics Card, that could explain why your FPS in Counter Strike is so low. Your PC is either using your Integrated Graphics Chipset or, worse, your CPU to render Counter Strike's visual aspects. This uses up a lot of CPU time and uses your computer's on-board RAM rather than your GPU's dedicated graphical RAM. Reinstall your Graphics Card's drivers to solve this problem.
allright i got a new problem right now but nevermind. it's out of the point to add some problem to the same thread, gonna make a new thread with different title now. thanks thelp, and i thought if you want to help me again just go here : http://www.tomshardware.com/answers/id-2221407/nvidia-geforce-gt540m-detected-screen-resolution-display-reinstalled-luck-nvidia-display.html