i think i had a similar problem before but thats usually after i update the drivers. if i remember correctly, right click on the TF2 and go to properties, then click launch options, and type in -autoconfig
then try running the game, it should load up and run but will be at very basic graphic settings. then your free to go back into launch options and delete -autoconfig and load up the game again.
i hope i remembered correctly as to how to do this!