I was recently setting up IIS 7.5 on Windows 2008 R2 for an ASP.NET site and came across the following 500 error:
Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list.
After a bit of searching, it turns out ASP.NET was not completely installed with IIS even though I checked that box in the "Add Feature" dialog. I found a number of suggestions but found this command. It fixed my issues and got rid of the error.
For a 32 bit system, use the