Question Details:

I have a hard drive from an old computer that has some interesting data I would like to recover.

Answer:

GoBack makes some changes to the drive's MBR.

You need a copy of GoBack to resolve this problem, the solution will not work with the drive mounted externally; it needs an ATA channel (PATA or SATA)

1. Make sure the drive you are trying to recover information from is not installed.
2. Install GoBack on your primary drive.
3. Turn off the computer and install the second drive.
4. Reboot the computer and GoBack should recognize the 2nd drive and "reconnect" to its MBR
5. Recover yout files and uninstall GoBack.

If this does not work try to use GetDataBack.