You can remove the old program or, get information (select icon, command + i) on a filetype that you want to open in the new program. (i.e. .psd for photoshop) then choose the open with tab. Then choose your new program from the list (may have to choose other... and locate it). Finally click the change all button.
Every icon you double click with the .psd extension, for example, will be open with the new version of the program. You will have to repeat this for every type of filetype you want to be able to double click and have open with the new program.