How can I clear key bindigs so that I don't have any buttons for volume adjustment and such and only one button for all actions. Is it possible In some file? I know how I could do it in options but that would be really time consuming.

Edit the CONTROL.INI file in your Outcast install directory and delete the entries you don't want.

Thanks
Another question about key binding. I have tried Clearin all but necessary bindings for couple times now. First I cleared all control bindings from control.ini. Game worked fine but I hadn't noticed that also non-bindable Escape and mouse axises were there. So I started again, made everything the same way exept I didn't remove axises and escape. But then the game stopped working (crashed at loading screen). I started again again and this time I carefully cleared the lines and removed those vertical lines before binds that seems to indicate how many buttons are selected but still the same result, crash at loading screen.

I use a more "primitive" approach. For example, I use W, A, S and D for movement. So, as you can bind each function to up to three different keys, I just bind three of those, for example W, A and S, to what I want to clear, in this case "Volume up". Then, I do the same for "Volume down", which causes all the bindings from "Volume up" to get removed, because each key can only be bound to a single function. When I'm done, I just bind them as the movement keys again. Like before, this will remove those three keys from any other function they might be bound to.
I guess that's a bad explanation, but hopefully it's understandable. In any case, this should get you the same result without the danger of "breaking" anything :)

Yeah, that is that "really time consuming" way I mentioned. Anyway I think I'm just going to do it the "time consuming" way as the "fast" way has already taken me more time than what the slow way would have taken :D