If it is only the one game easiest way to set it up is,
1. Open CCC and go to the 3D options.
2. Make the settings the way you want them for HL1
3. Click on Options near the top right and from the dropdown select Profiles/Profile Manager.
4. Give it a name, click on Activation and decide how you activate the profile (using a shortcut, hotkey, or systray icon). *
5. Repeat with all settings at default.
* Seeing as you are only looking at 2 profiles it would probably be easier to use the hotkey method of activating the profile, just need to remember to use it before starting the game. If you use the systray icon you could also do it that way. If you go the shortcut route you need to remember which shortcut is for the profile and which is the one with the profile (haven't used this method in quite a while, but I think the shortcut icon gets changed but not sure).