First off reset any custom video tweaks you've done.
Remove any custom .cfg files to a temp folder on your desktop or wherever you prefer,
Reset any custom tweaks set in your video drives.
Next find the \Program FiIes (x86)\Steam\SteamApps\common\rage\base\default.cfg file and remove it to your desktop.
Exit steam and launch Rage "Run As Administrator"
This fixed the Failed to Load error and I'm able to play again. Hopefully it works for you.