The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.

Being new on IIS 7 i created a simple asp.net web site and deployed on IIS but against my expectaions of running it well, it comes with different sort of errors like corrupted configuration files etc
so i removed handlers , modules section from web.config file but then it came out the issue of mime types , handlers etc
after trying a lot of things including
registering asp.net user,giving rigts to iis_user to that particular web directory
and
After read serveral articles about this, I found that we can change overrideModeDefault from deny to allow both for handlers and modules in the %windir%\system32\inetsrv\config\applicationHost.config. Alternatively, We can use %windir%\system32\inetsrv\appcmd command to do the same thing, e.g: %windir%\system32\inetsrv\appcmd unlock config -section:system.webServer/handlers.
But, I found another solution to this problem, which you don't need change the overrideModeDefault attribute of the system.webServer configuration section. When you enable IIS7 in the control panel, please choose the appropriate sections under Internet Information Services > World Wide Web Services > Application Development Features
 i finally solve the issue by turning on asp.net features for IIS from windows features.