I run CS on my PC with windows XP sp2, it runs nice!
I found a patch that corrects the "blocky text" menu problem and other like in-game crashes. Someone told me that they were caused by non-power-of-two textures in the original game.
There are several copies of that patch, choose a server and...
NEW SOLUTION!!!
I found this fix, I tried it at my Phenom X3 + Nvidia 9600GSO and it works great!!!
I don't know who made this, but his work is excellent.
Download the file cs_fix_2009.zip (3.2 MB) here:
http://www.megaupload.com/?d=PDYY6KB0
or here...