Bizarro World
I just ran the app for the first time since yesterday morning and got a bunch of these events::
aspnet_wp.exe (PID: 4948) stopped unexpectedly.
Failed to execute the request because the ASP.NET process identity does not have read permissions to the global assembly cache. Error: 0x80070005 Access is denied.
Failed to initialize the AppDomain:/LM/W3SVC/1/Root/Graffiti
Exception: System.IO.FileLoadException
Message: Could not load file or assembly 'System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. Access is denied.
Googling this lot brought on suggestions to run aspnet_regiis, add permissions to GAC, add permissions to app folders, add permissions to \windows\Microsoft.NET and many more scary things.
The trouble is, I could run another ASP.NET 2.0 app in the folder right next door.
I didn't find a single suggestion to check that the aspnet user had permission to read the app folder - but when I went in there that was the problem. Somehow (and I'm trying to not ask myself why) the aspnet user was gone from a folder that has been running a web site on localhost for a month.
So, googlers, consider this another option.
P.S. Please don't let this be "a sign" that a repave is due.