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 itfor 64bit with 
appropriate Enable32bitApplication setting(value must 
be false).