I'd really like to know how to turn off fog In call of duty 2 because It makes my crappy gfx card lag
Change rendering mode to Direct X 7. I don't know if there is any other way to do that. Switching to Direct X 7 is the best way I know. If you are experiencing performance problems, I don't think disabling fog will help. Try disabling shadows or try switching to DX 7 mode. Many people are experiencing performance problems in CoD 2 and switching to DX 7 is usually fine for most of the users.
Please Dont double post - no matter how anxious you are to get an answer. It is against the forum rules.
As to your problem, check out codfiles.com for a "no smoke" mod which turns off most of the FX on the maps by editing the level gsc files. You can then play Toujane and Matmata with DX9 enabled and not get bad lag because of the fxs. But you have to have your own server. Its not a client fix - its a server mod.