IIS7 not serving pages (ASPX) but just displays a blank page

I created a new IIS website with ApplicationPoolIdentity as the identity and .NET framework set to v4.0. In my hosts file I set my localhost to point to my test.dev domain (127.0.0.1 test.dev). When I tried viewing the site all I got back as a blank page.

What I tried: 

1. Installing all IIS components as I thought I might have missed some - this didn't help
2. Add full control permissions to my web folder for the ApplicationPoolIdentity (http://stackoverflow.com/questions/7334216/iis7-permissions-overview-applicationpoolidentity) - this didn't help
3. Registered .NET 4 with this command: C:\Windows\Microsoft.NET\Framework\v4.0.30319 C:\Windows\Microsoft.NET\Framework\v4.0.30319> aspnet_regiis.exe -i - This WORKED!!!

Umbraco packages throws error installedPackages.config is denied

This was happening on IIS7.5 and the error message said I should add ASPNET account to the security of the file. Instead (as I was using ApplicationPoolIdentity) I removed the Read-Only flag on the packages folder and this fixed my problem.