Recently, I had this problem where my MVC 3 site on IIS 8 was not rendering correctly. In fact amazingly when I checked fiddler those requests were throwing HTTP 500 errors. After, unsuccessfully searching online for a solution, I resorted to trial and error editing of the web.config file.
Previously, to add MIME types to IIS, I had this section in the web.config.
<mimeMap fileExtension=".mp4" mimeType="video/mp4" />
<mimeMap fileExtension=".ogv" mimeType="video/ogg" />
However, this doesn't seem to be sitting well with IIS 8. Once, I removed that section all else worked fine.