Second hard Drive – Retreiving Data

I have a laptop running Vista, and I have a hard drive that I pulled off from an older computer which I had Windows XP running on it. I put that hard drive in a External enclosure and hooked it into my laptop using the USB cable.

My laptop does not see a drive letter associated with the new external drive. But when I go to my Device manager it sees it and when I go to my ADMINISTRATIVE TOOLS | COMPUTER MANAGEMENT | DISK MANAGEMENT, it sees the drive but it doesnt assign a drive letter to it. When I right click on it, the only option I can choose is HELP.

The external hard drive is not corrupted. Is this due to having WinXP on it? How do I get the data off it? I have 120 gb of music on it.

Thanks