Go to cstrike\addons\metamod\plugins.ini file and disable by adding a semicolon (

in front of each line You have there. Then start the game and see if CS at least is able to load Your metamod. If even that is a problem for Your CS - in most cases helpful is just reisntalling the steam and everything.
Note:
CS 1.6/CZERO non-steam versions aren't supported. Your legall version should work normally.