New External Hard Drive Help

I just made a new external hard drive with an old hhd from a laptop. All the files, besides the basic ones that came with the computer, are gone. I just want to know what i should delete. Should I save the windows files or delete them so I can have more room for music and such. If possable I would like to save the files in window media player in the hhd.

Start fresh and format it.

thanks