Accessing former XP drive as second drive under Windows 7 without Chowning

Windows Vista and 7 has a complete different security model then XP. Furthermore, when installing Vista/7 the OS is not aware of previous users that was on the old harddrive, and therefore it will treat the old harddrive as alien.

"If you have plenty of disk space available, you could try taking a disk image/snapshot using something like ghost/true image

If the drive is failing, that obviously complicates things, but most imaging tools have options to ignore errors and copy what it can. However this make it harder to determine what parts have been copied correctly.

Once you have the image, you could try restoring this to a real drive or partition or to a new drive in a Virtual Machine (eg Virtual XP) and then use the take ownership of the files."