I moved the hard drive from one machine (Win 7) to another (XP) and now certain folders tell me "Access denied". I am logged in as an administrator. I had a different account on the other machine. Neither account authenticated to anything besides the local machine. The old machine is apparently dead, so I can't do anything in there like change permissions, etc. How can I access these files?

Edit:

After changing the ownerships of all the files and folders on the drive, I am getting a different error. And it is troubling me deeply.

"xxx refers to a location that is unavailable. It could be on a hard drive on this computer, or on a network. Check to make sure that the disk is properly inserted, or that you are connected to the Internet or your network, and then try again. If it still cannot be located, the information might have been moved to a different location."

No change after rebooting. Any ideas? Surely the files are still there, right?