IIS Service Unavailable after setting 32bit (IIS 6.0)

I was having the "Service Unavailable" issue after I changed IIS to 32 bit mode. I found a solution that worked for me:

Our problem was that ASP.net was trying to run a 64 bit DLL, which failed after we reset IIS to 32 bit mode. All we needed to do was change the bitness of the ASP.net DLL to 32 bit mode. To do that, first turn on the server service. Once that service is running, run the following:

C:\Windows\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis.exe -i -enable

This will reinstall ASP.NET with the appropriate bitness.