I recently had a Windows 2003 Server that for some reason would not return even a single page through IIS. I was getting the dreaded “Service Not Available” error. Upon investigation I noticed several events in the Windows Event log with ID 1002 and 1009.

After some googling a few dozen searches on the subject I was pointed back at a corrupted installation of the .NET Framework version 2. I attempted to remove just the .NET framework but I could still not get a page to load through IIS. I next removed IIS completely then reinstalled.
After the reinstall I needed to manually re register .NET with IIS.
Here is the command in case someone else might come across this problem.
Open a command prompt and go to “C:WINDOWSMicrosoft.NETFrameworkv2.0.50727 (change folder to corresponds to your exact version of .NET 2.0)
Run

aspnet_regiis.exe -i

After running the above command I ran

iisreset

to restart the IIS services. I was them able to get IIS working again.
Hope this helps.