Hallo Lynn,
just tried like described in Support-FAQs (17/ Problem mit die Auflösung - Vista), but it looks like it won't work in Windows 7 (I'm using Win7 Ulitimate x64).
The settings won't be used, the only thing thats different, since that I set the config-files to writeprotected, is that if I try to change settings ingame, it's always asking to restart the game to enable the changes, but that's of course not working.