Transferring files using external drive

I bought a WD Passport External Hard drive to back up my Mac before I went away. While i was away people were using their ext hard drives to transfer files (movies TV programmes etc) between their computers. How do I transfer files off my mac to a PC using the passport? When i load it onto the PC i dont see any of the files on my ext hard drive…

The external drive has to be formatted to FAT 32 in order to be read by both PC’s and Mac’s.  If the drive is formatted in HFS+, Windows won’t be able to read the files.  Realize that FAT 32 has a file size limitation of 4 GB’s, and that there is always a possibility of file corruption when passing files between Mac’s and PC’s.  So, keep your data backed up.