If you use Drupal on a regular basis, chances are that you will want to apply a patch to a module at some point in time. Perhaps somebody has posted a patch in the issue queue that sounds like it will address a problem you are having. Patching files on windows is simple. Just follow these steps.
1. You will need to download the patch software. You can download the Patch program at http://gnuwin32.sourceforge.net/packages/patch.htm
2. Run the setup file and install the program using all of the default settings.