Open previous blender version

Hi! I think this is a kinda noob question, but i couldn’t find any answer. I have multiple versions of blender installed, how do i open a previous version of it?
Actually i’m comparing AMD gpu render time between 2.69 and 2.72, but of course, it’s opening by deafault the 2.72.

Thanks, but this is not my problem, i would like to know if i can somehow open the previously installed version of blender, but after taking a look around i think this is not possible. I asked this because in the Blender folder you can see other folders named as the versions you installed, so i thought i could open them, but now i think they are just settings and user data. Now i installed 2.69 again in a different folder.