Back To The Future Episode 4 Won't Start

[Supernaut88]

I got given all Back To The Future episodes as a gift on steam for Christmas and have been thoroughly enjoying Episode 1, 2 and 3 with only an occasional glitch where everything slows down and most of the screen is black, but going to the menu and back usually fixed this so I'm not that bothered.

However I just finished Episode 3 today and when I went to load episode 4 I am getting a message that says BackToTheFuture104.exe has stopped working and under details I am getting:

Problem signature:
Problem Event Name: APPCRASH
Application Name: BackToTheFuture104.exe
Application Version: 2011.4.7.56337
Application Timestamp: 4d9dfa47
Fault Module Name: StackHash_c814
Fault Module Version: 6.1.7601.17725
Fault Module Timestamp: 4ec49b8f
Exception Code: c0000374
Exception Offset: 000ce6c3
OS Version: 6.1.7601.2.1.0.768.3
Locale ID: 3081
Additional Information 1: c814
Additional Information 2: c8140d617011641d13062882e10351de
Additional Information 3: 521d
Additional Information 4: 521d73dc2d1605ac5b49f41f5b0615d6

I have also run dxdiag, the .txt is attached to this post.

I have tried:
-manually installing directx through the episode 4 folder in steamapps
-verifying the intergrity of the game cache
-re-installing the game
-doing a clean boot to make sure nothing is interfering with the game
-replacing the prefs.prop file with one I found posted on a forum
-restarting steam and my computer multiple times
-updating graphics drivers
-running the game as administrator



I am completely lost as to what to try next. Especially considering the first three episodes worked fine. I hope I don't go through this again with Episode 5