If you are looking for an easy way to run ePubCheck or KindleGen on files in Windows, you can create a batch file (like "ePubCheck.bat"), put the proper DOS command into the file pointing to the correct location and name of the ePubCheck or KindleGen program, and just drop files onto it. For examples, download the batch scripts for ePubCheck and KindleGen here and open them in a text edior like Notepad.