Need to Use Both Reader and Pro on One Machine

Hello. As the title reads, I hope to be able to find a way to install both Acrobat Reader and Pro on a computer, or some similar result.

The reason for it: One person who uses the computer in question does graphic design work. They also have a work computer (elsewhere), and a server that is also frequently used for some things. They are the only user with an Adobe Creative lisence, and other people who use the machine have become unable to open PDF files.

It used to function this way, but has quit doing so (by design, apparently, looking at other dicussions). When I tried reinstalling Reader I received the following message: Old/New Acrobat version already installed.

Is there any way to make this work? No one else needs the ability to edit, or otherwise manipulate, PDFs like that, but they do. Other than them, all we need is the ability to read PDF files.