This literally drove me fucking nuts for the whole damn morning. I checked everything I could think of, but when WebMatrix was run, it would hang for abut 5-10 seconds and then the “WebMatrix has stopped working” message would appear on the screen. What was the fix? Go to this folder C:\Users\USERNAME\AppData\Local\Microsoft and rename the WebMatrix directory. I added .bak to the directory and when I ran the application it fired up as it should and recreated the folder minus the junk that was causing the issue. This fix took about 2 hours of cursing and trying a few things, another hour of researching the issue and seeing what everyone else tried, finally about 20 seconds to implement the fix. Hopefully, next time I remember to come check here for the fix first.