HL2 Configuration file

[MonkeyWrench4000]

I am trying to Clear a glitch out of HL2 and CS:S, and cannot seem to find the configuration file that stores the information for your video settings. I have deleted the entire game, and steam, and then deleted the remaining folders, and also checked to see if there was a folder in application data, yet when I reinstall, it still knows my last set video settings.

I need to know where the configuration file that holds this info is. Thanks.