Error message when trying to enable ASP.NET in "Turn Windows features on or off"

view full story

http://serverfault.com – I've deployed a site to IIS on my local machine and am trying to access one of the handlers in the browser.I keep getting the folowing error: HTTP Error 500.21 - Internal Server Error Most likely causes: Managed handler is used; however, ASP.NET is not installed or is not installed completely. I checked in Add or remove programs -> Turn Windows features on or off -> IIS -> WWW Services -> Application Development Features and indeed ASP.NET is not checked but when I try check it I get this error: An error has occurred. Not all features were successfully changed. So how can I enabled ASP. (HowTos)