The whole concept of "installing" is a stupefied Microsoft idea, there shouldn't really be much, or anything, you have to "install" for a program.
As for Code::Blocks, the configuration is one of two things to keep an eye on, and file associations are the other.
If you want to use two versions with the same config, that will ... probably... work, if they are somewhat similar versions, but it may spectacularly fail, too (no guarantees there).
If you just copy the existing config into the existing Code::Blocks executable dir, it will use that one instead of the global one, and you're on the safe side. Code::Blocks is relocatable, or "portable" as people like to call it insofar as it will consider any config found in its executable directory first, if not told anything different.
Alternatively, you can just start each version of Code::Blocks from a link or start menu entry that has the --profile switch on the commandline, and specify a config file that is whereever you like. You can even use this to start the same version with different settings on different occasions, if you need to do that for some reason (Code::Blocks developers do that since if you accidentially fuck up your config while playing around, it's not the one you need to run the program to fix things!).
File associations, i.e. which program will be launched if you double-click a .cpp file, are the only kind of "install" thing that you need to do, and you can conveniently manage these from within the running Code::Blocks instance ("Environment Settings").
