If you are running mods/addons/plugins, try testing from a clean install of rfactor with no mods/addons/plugins as they may be causing an issue. You can do this simply by installing rfactor into a new clean folder (e.g. "rFactor Clean") and testing from there. However, if you have UAC (User Account Control) enabled, it may load your prior settings and the problem may still be there. So when running rfactor, right-click and selecting "Run As Administrator..." (as this is a common issue with Windows 7 with UAC enabled).