Shoutbox

set the graphic settings to the lowest possible on CS

Options -> Video -> Advanced ..

With "look into the manual", I mean: look at the proper source for such questions... Specifically for CS, why not ask your questions on the CS forums?
http://www.forumplanet.com/counterstrike/

The chances that they could answer you in extreme detail is much higher there than it is here.

In fact, there are already threads there which will answer your questions, and even a very recent one wich repeats what has been said on those forums more than once: http://www.forumplanet.com/counterstrike/topic.as...d=8447&tid=1798004
and for example also:
http://www.forumplanet.com/counterstrike/topic.as...d=8447&tid=1576031

Turning everything down to the lowest possible graphic setting, and then slowly turning everything up is what I normally do. Mind you, the biggest chokepoint for FPS is (believe it or not) RAM. When your computer has to go and fetch some data from the disk, it eats away at your processing power, which is why you get such a low framerate. RAM's pretty cheap ($50 CAD for a 512 DIMM), so if you really want to squeeze out some awesome framerates, upgrade your RAM.