Consider anything you changed in between the game working and it not working. Windows updates, driver updates etc and roll them back or remove them.
Not sure if modified files in your F1 install remain on a re-install, but camera mods have been known to cause some problems.
Also consider uninstalling GFWL and reinstalling, as ive heard this can cause problems with F1 crashing/not starting too.
HAve a search on this forum using keywords - there have been a lot of 'excutable stopped working' threads before I think.