Maximum PC

The problem is I have a Maxtor Diamond 8 Plus that I was trying to use as a spare external drive via a USB hookup, when I hook this up to my laptop, a Dell Inspiron 5150 running Windows XP SP3, yes I know, but I got this through my work for a really good deal, but I regress; anyway the laptop does recognize that the hard drive is plugged as it gives me the “USB storage device” is plugged in and I have the little safe to pull icon in the system tray. However it does not show up in the My Documents, My Computer or in Disk Management. It does show up in the Device Manager under Disk Drive and under Universal Serial Bus Controller “Location 0 (USB to ATA/ATAPI bridge)” though... I also tried this on my desktop PC and had the same issue it shows up only under Device manager but nowhere else. I have a feeling the drive is incompatible maybe or faulty as it was a factory refurbished item but I just don’t know how to verify if it is the drive or a Windows issue. One note is I originally got this drive to load Windows XP on my desktop but due to misinformation from a rep of the make of the PC, that models board has issues with this specific drive it seems, it would not load so I got a brand that would work and thought I would keep the Maxtor for a external drive to the laptop. Any help will much appreciated.

P.S. I am working and will have off an on access to a computer so I might have a slow response