I need 9x to open various online forms which will not open with older versions, etc but I also need to use Acrobat for editing, adding/deleting pages. Nowhere in the download info for Reader 9 does it say it will diable prior full versions of Acrobat. No matter what I do, right click "open with" and even trying to open the application .exe file directly will let me open my paid for, legitimate version of Acrobat. Win xp.
Unfortunately they don't make it obvious enough but having both Acrobat and Reader products on the same Windows machine is not supported nor recommended due to many various issues that can be caused.
You can go to task manager and quite out of Reader if you want to use Acrobat.
Before you start Adobe Acrobat kill all running processes of Adobe Reader in the task manager.