I've checked my installed programs in windows 7 machine. In it there are several copies of Microsoft Visual C++ were installed. I know they provide support files for various programs and softwares I've installed in past.
But If I uninstall the older one, will the associated software or games misbehave??? or should I keep them installed?
And if I have to keep them all installed for the sake of their associated softwares, How can I find out some useless copies of this MSVC++ if their main programs were uninstalled already????
Thanks in advance :)

You did not mention the games you intend to make sure will work. Even if you did, I doubt anyone here is developing all the games, so an exact answer is unlikely to be given here.
However, new versions of any software should be as much compatible with older versions as possible and you should keep that in mind when you see all the versions, so you should be able to keep only the latest installation.
However, the way to find out is to perform the following algorithm