I have borrowed a mass storage device from a friend who has a Mac... I have a Sony Vaio. The device is a Seagate. When I plug the device into my computer, the USB does not even register. I have looked for a pragram that will convert them, but I don't know what I am looking for.
The device is probably formatted as Journaled which Windows cannot read. In order to use it with a PC, you need to reformat it as NTFS or FAT. But then again, by doing so you're going to lose all data on it, and since it's not yours, I'm not sure if that's an option.
The mass storage was probably formatted for Mac only and not PC. Your best bet is to have your friend pull the files off and transfer them to a mass storage device you either use or format on your machine.