I have a hard drive that was giving me an unmountable boot volume and i was going to slave it with my other comuter using a USB adapter. But when I did that the drive would not show up under "My Computer" but it would be in "Device Manager" and when I try to get into it under Disk Mangement it freezes up. Is there any software or utilities out there that would allow me to access it since windows is not able to.

Any idea why unmountable boot volume appeared? Did it used to work, but just stopped for no apparent reason?

It sounds like a bad drive. Windows hangs when it tries to access the disks because it is not working properly (most likely).

You could try a diagnostic program to see if it is really bad or not. There's also a good program that may be able to fix it well enough so its readable again named HDD Regen... But it will require a lot of time to scan. It can ONLY fix bad sectors, so if the problem is anything else, it may not be of much use.