Jim,
Sounds like you installed the Acrobat Reader, then installed Acrobat "proper", then removed Reader? What probably happened was when you removed Reader, it also removed the file association of "pdf" files. You can either just re-install Acrobat "proper" again or associate "pdf" to Acrobat.
To perform the latter, assuming that you have Win XP, you open the "Control panel", open "Folder Options", click on the "File Types" tab, scroll down and select "PDF" extensions and click the button "Change" and then select "Adobe Acrobat" instead of "Abobe Reader".
That should solve the issue with the file association.
