I am having issues with playing challenge mode in Arkham Asylum GOTY edition on Steam. I played through all of the story mode and had zero problems (and absolutely loved it, amazing game). Whenever I try to play a challenge mode it will go to the loading screen for about 2 minutes or so and then it will go black and exit the game and steam completely. One time (out of about 10 tries) it went past the loading screen and came to the intro of the challenge mode, but then froze there and eventually completely exited. I've tried disabling PhysX and completely uninstalling the game (and deleting all local files) and reinstalling, but to no avail. My PC spec are as follows:

Processor: Intel(R) Core(TM) i7-4790K CPU @4.00GHz
Installed Memory (RAM): 16.0 GB (15.9 GB usable)
System type: 64-bit Operating System, x64-based processor
Graphics: Nvidia GeForce GTX 780
Graphics Driver: Version 378.49

If you need to know anything about my PC specs/settings feel free to let me know. Any help on this matter would be greatly appreciated; I can't wait to knock out the rest of my Steam achievements for the game!

Thanks so much!