1TB My Book - Works on Laptop but not Desktop. Passport drive works fine on both


I have been searching around for a while now and I hope someone can help me. I have a Western Digital My Book 1 TB external (USB 2.0) drive that I have been using for a while. I can get it to recognize and work fine on my Windows 7 laptop, but it does not work on my Desktop. When its plugged into the desktop I only see “My Book” as an “Unspecified” device under Devices and Printers. Disk Management does not see the drive. I can however plug in my 750 GB Passport drive and it works fine in the desktop. Any ideas?


No  ideas?