I am using Windows NT since Vs3.1 in 1994 and IIS since 1.0 in 1996. So I have a bit experience with these systems and still use mostly Microsoft technologies.

IIS Troubleshooting tools:

• Process Monitor - Finding out about failing file access
• Test-WebSite - PowerShell scripts for testing an IIS web site and suggesting fixes

When I make money it is usually as a .NET developer.