When trying to build my game, it starts to build, but then Unity freezes. I have tried closing Unity and opening it but the problem persists. I am quite sure I have had this problem in the past but cannot remember how to fix it. Any help is greatly appreciated. Thanks.
Thats not a log file. Please see this link, it tells you where to find the log file. It is a text file that contains a lot more information. http://docs.unity3d.com/Manual/LogFiles.html
You probably just have a different text editor. Do File/Save-As and it should give you the location of the file. Then navigate to that directory and grab the 2 files. This link also tells you where to find the files http://docs.unity3d.com/Manual/LogFiles.html
AppData is a hidden folder. You can change settings to display hidden files/folders, or you can navigate there in the command prompt which might be easier. From a command prompt in C:\Users<username>\ you would just type:
cd AppData\Local\Unity\Editor
Then open that folder in Windows Explorer with:
explorer .
Note the space followed by the period “.” which tells explorer to open the folder you are in.