After installing Acrobat Reader 9.0 on Vista Ultimate SP1, I am no longer able to associate the pdf extension with Reader. When attempting to change the pdf file association, Reader is not offered as an option. When clicking the Browse button and pointing to the Reader 9.0 file, it still is not offered as an option. Reader works fine when loading files from within the application.
Do I need to edit the Registry? Which key and what value?
Have a look at
It looks like you have to remove any existing associations before
trying to apply the correct ones.