Configuring IIS to Run 32-bit or 64 bit Applications on 64-bit Windows (IIS 6.0)

I was trying VMWare Server on a 64 bit Windows Server 2003 machine to see if I can use it to create a 64 bit guest OS.

It did not work. My CPU does not have the magic bits.

So I uninstalled it.

However, my 64 bit Virtual Server stops working. The administration web page simply refuses to load, with the error message "service unavailable".

After some fun investigation, I finally figure out what is going on.

VMWare Server setup changed the IIS configuration to run 32 bit application. After uninstall it, it did not change it back.

After manually change IIS to run 64 bit application, Virtual Server is working happily.

Here is how to switch IIS to run 32 bit or 64 bit applications.