Windows 8.1 / Windows 10 breaks my ASP.NET / IIS : “Service unavailable”

Question

With Windows 8.1 finally released to MSDN/Technet today I came across the following issue running my ASP.NET application after doing an in place upgrade with Win 8.1 RTM:

Answer 1

I just ran in to this issue after an update. All of the app pools where stopped! Starting them resolved the issue.