IIS 6.0 suddenly shows directory listing instead of MVC 3 app

1. Open Command prompt
2. Go to C:\Windows\Microsoft.NET\Framework\<version> folder.
3. Run aspnet_regiis -i

That's all!

A little late.... But as I was receiving the same result.

My Application Pool was targeting the wrong .Net version (should be same as web app Target Framework). Simply adjusted within the "Set Application Pool Defaults" option, restarted and it was solved.

Hope it helps someone.

I had a similar problem. The IIS root path had been changed by a collegue. The solution was to fix the "Physical Path" in the "Advanced Settings" of the Default Web Site.