WebMatrix not starting, ERROR: IIS 7.5 Express could not be initialized

Hi, I am new to IIS and ASP.NET, and I am trying to get Microsoft WebMatrix to work.

I downloaded and installed it, but, when I tried to start it, it gave me this:

"ERROR: IIS 7.5 Express could not be initialized."

WebMatrix will not start.

I tried uninstalling and re-installing IIS 7.5 Express, but there were no changes.

Somebody told me that it might be due to the fact that I had turned IIS on and off again through the "Turn Windows Features On or Off," settings in Windows 7. If so, how do I fix this?

Does anybody know how can I get WebMatrix and IIS 7.5 Express working?

Any advice is very much appreciated.

HP Pavilion dv6, Windows 7 SP1 64bit, 4GB RAM, Running in a LAN