how can i get the 1.7 version cuz its not letting me play the server and if i do get it will i still be able to get onto to other servers

Do a search in any search engin for "cod4 patches" and then find a 1.7 version download for multi-player. Install this on your PC, but once installed you will not get to play servers that still run the 1.6 version, or at least I was not able to when I installed the patch. Because my server is still running the 1.6 I had to reinstall the game and get the 1.6 patch to step back to it.

I am contemplating upgrading both my server and pc to the 1.7 version.

Filefront has the patch

http://www.filefront.com/10829906/Call-of-Duty-4-Modern-Warfare-v1.7-Patch/