I don't know why this isn't posted in the Support FAQ, this "workaround" (more so than a fix) seems to have solved the vast majority of problems that STEAM users are having with Walking Dead and this quick solution is usually buried in an existing thread vs being the top post.
So here it is:
If you have WD through STEAM and cannot play because you are crashing (and in some cases, other issues like never connecting to Telltale servers)...simply disconnect your machine from the internet.
You can do this easily by:1) Physically unplug your network cable (CAT 5) from your machine.
2) Physically unplug your network cable (CAT 5) from your router (or modem) that connects to your machine.
3) Disable the internet connection in your Network and Sharing Settings.In Win 7*:
Control Panel --> Network and Sharing Center --> Change Adapter Settings (upper left) --> select your network and RIGHT-CLICK --> select "Disable".
Do this after you open STEAM but before you start WD.
The problem is not your machine. It is not STEAM. It is not your installation of the game. The problem is Telltale's code and/or servers that the game tries to connect to (and perhaps that is why they don't want to put it in their Support FAQ).
I'm a STEAM user who couldn't play until I found this "fix", and I approve of this message.
* Been a while since I've been on another system other than Win 7 so I can't recall the path and settings to the Network CP for them. If you remember or if you have a system other than Win 7, I'll edit this post to include it if you paste the path.