I got this error when I was configuring my website with IIS7 (for windows7 OS)
"This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false"."
So the solution is :-
1. Go to start menu.
2. Select control panel.
3. Then select Uninstall a program.
4. After that select "Turn windows features on or off" from left panel.
5. From the content select "Internet Information Service" and expand it. Then check all the features.
6. Then click ok.
After doing the above steps, register the asp.net application with IIS7.
Following are the steps to register your asp.net application with IIS
1. Go to visual studio command prompt.
2. There type "aspnet_regiis -i" then hit enter key.
3. Now it will register your asp.net application with IIS.
After doing the above steps, try to browse your website on the browser.
Hope this will helpful for users.