I currently have Adobe Reader 4.0. I want to install 9.1 because I think the old version is preventing me opening some files. Can I install the new nersion without uninstalling the old one first or must I uninstall 4.0 first?
I believe that 9 wil uninstall al older versions although I haven't tested that with a version that old (only as far back as 5).
If you want to play it safe, uninstall 4 first (you don't want to have both instaled on the same machine). It only takes a couple of minutes.