Unlocking Security on NTFS: Windows Files

One of my Windows XP computers got broken in international mail. I still have the hard disk and want to retrieve the data from it.

The problem is that all files in the Windows directory are protected, and I cannot open or copy them. Actually, I did find a way to set user rights for files -but only one at a time.

Is there a way to set permissions for the entire Windows directory at once so I can backup and retrieve my data?

Thanks in advance