Vista - Unable to access files on external hard drive

I have just recently bought a new pc with Windows Vista Home
Premium. Today i purchased an external hard drive enclosure for my old hard drive from my old XP pc. I open the XP hard drive on my Vista, im able to see all the file names that are on it...but it will not let me access any of the files - it says I do not have the privileges to access these files, even though I am an administrator. i have already done the process of Right click, properties, and then attempt to add my username to the list and/or give full access but it still won't let me in. and iv tried doing what this site says Add "Take Ownership" to right-click menu in Vista and it did not work. what can i do?

Once you have ownership of the hdd permissions you have to apply it to all the folders inside the drive, these ones I use for my external hdd because they don't cause a problem between computers.

could you please explain more how i would do that DMEX