Webapi issues on IIS

Ran into issues when WebApi app was deployed to IIS. For example got this error:
Handler "ExtensionlessUrlHandler-Integrated-4.0" has a bad module "ManagedPipelineHandler" in its module list

To Resolve:

1) Need to register asp.net. But aspnet_regiis.exe -i did not work on Windows 8.1

However, this worked:

If you're running into this error with Windows 8/Windows Server 2012 and .Net 4.5 follow these instructions here: http://www.britishdeveloper.co.uk/2013/01/handler-extensionlessurlhandler.html

Go to "turn Windows features on or off" Then Internet Information Services Then World Wide Web Services Then Application Development Features And then enable ASP.NET 4.5

http://www.britishdeveloper.co.uk/2013/01/handler-extensionlessurlhandler.html

2)
Also did this:

I also was getting the same problem but after brain storming with IIS and google for many hours . I found out the solution. This error is coming because some setting is disabled in IIS "applicationHost.config" Below are the steps to solution:

step 1: Go to C:\Windows\System32\inetsrv\config\applicationHost.config and open in notepad

step 2: change the follwing key value present in

a) 

change this value from "Deny" to "Allow"

b) 

 change this value from "Deny" to "Allow"

It worked for me.

Per this article:

http://stackoverflow.com/questions/20048486/http-error-500-19-and-error-code-0x80070021