Running 32-bit/64-bit IIS

IIS7 – Running 32-bit and 64-bit ASP.NET versions at the same time on different worker processes

Below is how you do it from IIS7 manager:

1. Right click on the Application Pool and select “Advanced Settings…” or select the same from the Actions pane after selecting the Application pool
2. Change the “Enable 32-bit Applications” to True (if you want the application pool to spawn in a 32-bit mode)
3. Click OK