HTTP Error 500.19 - Internal Server Error in IIS 7.0 – How to fix it

I just upgraded my pc at work from XP to Windows Vista Business, yes I actually mean upgraded rather than a clean install. Ordinarily I wouldn’t have gone down the upgrade route but for various reasons I couldn’t afford to wipe my pc and start again at the moment.

Everything seemed ok, the upgrade process, though a little slow, completed alright. However none of my websites that were running in IIS were now running; I was getting HTTP Error 500.19 – Internal Server Error in IIS 7.0, not good. I checked permissions on applicationHost.config and couldn’t see anything wrong, then, after figuring out how to enable Request Tracing and realising there was nothing in the folder, so nothing wrong. Next I had a look at my web.config file, though I didn’t really expect there to be anything wrong with the config as I had been using this site before upgrading to Vista.  Nothing out of the ordinary there.

Finally I decided to reinstall the .Net feature of IIS 7.0, to do this go to:
Control Panel > Programs and Features, then from the Tasks bar on the left side select Turn Windows features on or off, expand Internet Information Services, then World Wide Web Services, Application Development Features then uncheck ASP.NET click OK and then come back and check the boxHope this helps