xcopy [source] [destination] /c /h /e /k /r

Souce/destination can be something like c: or a directory. This will just copy the files from one drive/directory to another. If you are using Win9x, you will have to sys the drive afterwards to make it bootable.

Example:

xcopy c:\*.* d: /c /h /e /k /r

will copy all of drive C: to drive D: