Hey there, Jeremy.
Basically if you don't mess around with partitions and as long as you don't write any data on it, you might be able to recover the files you need. However you'll need to find data recovery software for Windows, which is able to recover files from an HFS+ (or other Mac OS X File Systems) partition. You could check the suggestions from this article and see if any of the given options can do the trick: http://pcsupport.about.com/od/filerecovery/tp/free-file-recovery-programs.htm.
Once you recover your files, you should reformat it by using the NTFS File System if you're going to use that drive with a PC.
Hope that helps. Please let me know how it goes.
Boogieman_WD