I've tried fiddling around in the config files, but since I'm relatively new to Litestep I don't know what I'm doing.

Is it possible to change it so that instead of the Windows key opening the popup menu, it will open the KDE menu in the theme I'm using (Norman Bates KDE)?

Thanks

jKeyRWinKey !Whatever bang
jKeyLWinKey !Whatever bang
If its openning popup now. its probably specified that way on your personnal.rc or (one of the rcs on your personnal folder) you might want to comment that if you want to make it theme specific.

I'm probably missing something really obvious here, but it still opens the popup menu upon pressing either button after deleting these lines from my personal.rc:

jKeyLWinKey "!Popup"
jKeyRWinKey "!Popup"

I've reloaded LS and even rebooted the computer but it still does it, so there must be something else that's doing it.

Any ideas? :(

you didnt need to delete those commands.
what you need to do is change what it is that the keys execute.

jKeyLWinKey "!Popup" calls the popup menu
you need to change it to
jKeyLWinKey "!whatever it is that makes the kde menu appear"

Ideas:
1)your theme has the same line on the theme.rc
2)you are loading hotkey instead of jkey and there should be a different but similar hotkey line opening popup.
3)you are loading jkey but "jKeyUseHotkeyDef" is there and that hotkey similar line is being used.

Ok,add:(on your personal.rc)
HotkeyNoWinKeyPopup true