Weird... assuming the resolution is correct, then I would check the font size, in Windows 7 it is under Control Panel\Appearance and Personalization\Display, make sure it is set to Smaller - 100% (default), that can mess up not only installer but the client as well if it is set to anything else. Can also make sure they don't have anything set in "Set custom text size (DPI)", it should be set to 100%.