you should try setting some files as read-only such as :
- cstrike\resource\GameMenu.res
- cstrike\autoexec.cfg
- cstrike\config.cfg
- cstrike\userconfig.cfg
it will prevent them from being modified by 3rd party programs like those you can be victim of when joining some servers...
(please note that you have to remove their read-only attribute if you want to edit your in-game settings)