Resolution problem


After installing Darwin 1.0(.4?) on one of my hardrive partitions, I can't switch resolution in MacOS X PB (The only resolution availible is 640x480). Uninstalling Darwin has no effect. I don't know if Darwin is the cause to this, but it's the only clue I've got. Does anybody know how to change this manually (a file somewhere?), or is reinstalling PB the only choice I've got?