How to enable the 64bit compatibility on IIS6 and IIS7?

Sometimes, you will get the following error after deploying your web application (developed for 64 bit environment and if you referred to any GAC DLL in your application) on IIS 6 or IIS7.

Could not find the path of
C:\Windows\assembly\GAC_MSIL_<Dll Name>_<GAC ID>\Bin

This error occurs because of your IIS currently not supporting 64bit applications, so you need to enable the 64bit compatibility on IIS and you can resolve this by using the following steps on different IIS versions based your requirements.

For IIS6:

Step 1:  Click Start, click Run, type cmd, and then click OK.
Step 2:  Type the following command to disable the 32-bit mode:

         cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET
         W3SVC/AppPools/Enable32bitAppOnWin64 0

Step 3:  Type the following command to install the version of ASP.NET   
         2.0 and to install the script maps at the IIS root and under:

         %SYSTEMROOT%\Microsoft.NET\Framework64\v2.0.50727
         \aspnet_regiis.exe -i

Step 4:  Make sure that the status of ASP.NET version 2.0.50727 is set 
         to Allowed in the Web service extension list in Internet 
         Information Services Manager(if your application deployed on 
         windows 2003 or 2008).

For IIS7:

Step 1:  Open the Internet Information Service Manager  
         from Start Menu or Control Panel --> Administrative 
         Tools.
Step 2:  Expand  the Application Pools Node then find your Website 
         Application Pool then right click on it  then click on 
         Advanced Settings, it will popup the settings screen here you 
         need to set false for Enable32bitApplication.This settings may 
         affect your existing 32bit application,if you get any error on 
         your 32 applications then you reset the above setting and 
         create a new application pool just like existing on and use it 
         for 64bit with appropriate Enable32bitApplication setting
         (value must be false).