First of all, your first question has come up on SoPW before. You could try doing a Super Search to find the answer.

If you used a tool like ppm or cpan to install your modules, they might be able to tell you which modules they installed.

You might be interested in Module::CoreList. It lists which modules are part of each version of Perl. Your distribution could have come with more than those modules, though. For example, ActivePerl includes libwin32, a library of Win32 modules.