Does it show an error message or does it crash, and if so does it generate a crash dump? (dump files are in C:\Users\abc\Documents\My Games\SimBin\Crash Dumps) This could have a variety of causes. Some general tips: Verify the games cache files after installing/updating (right click the game in steam, select properties and click the button in the local files tab). Run Steam and R3E exe files as admin (right click the exe file, select properties and tick the box in compatibility tab). Make sure all neccessary drivers are up to date. If you need more help we'd need more info on your system, so post your PC's specs please.
another thing: If you are using a Logitech-Wheel and you have the logitech-profiler running, try to close it before starting raceroom. Sometimes it has strange behavior on some systems... Can you give us some specs of your system?