Diagnosing 404 on IIS

I am running windows 7, and I'm having a problem getting sites in my IIS setup to work. I just get a 404 every time I try to browse to any of the sites.

I have previously installed Visual Studio, IIS, and I开发者_StackOverflow社区IS Express on my machine.

Yesterday I installed Visual Studio SP1 (which I think installs IIS Express 7.5).

I noticed the problem yesterday, so uninstalled IIS and IISExpress. I reinstalled both of them, but still no joy. How can I diagnose this issue?

UPDATE: Almost given up with IIS on my machine. Something is screwed up. I noticed that the security settings on the inetpub folder and subfolders were in some case incorrect. The owner of some of those folders was unable to be displayed.

I uninstalled IIS, did a scandisk, deleted the sub folders under inetpub. Set the owner to my machine administrator user group on the inetpub dir, reinstalled IIS.

Still screwed up. IIS Express still works, so that is probably what I am going to rely on from now on.