Could not load file or assembly or one of its dependencies. Access is denied

I was moving an older .Net 2.0 web service to a new IIS box.  I set up everything but each time I loaded the application I got this annoying error!  Cursory search will reveal a miriad of potential issues.

Here are the usual culprits.

1. IUSR_USR or impersonated account does not have access to Temporary ASP.NET in Framework.
2. Account does not have access to the inetpub/wwwroot or wherever the website is hosted.
3. Checked impersonation.

This was the issue.  I was using an expired service account which had come over with the web.config file.  Mapped the Authentication > ASP.NET Impersonation to the valid service account and that fixed it!