Yeh, the above post is exactly right for Win2k, I'm fairly sure it is the same for XP. Unfortunately I don't have either installed on any machines here so I can't give you the exact tabs. However, from memory there are three tabs, so if you log in as an Administrator (normally 'Administrator') and right click on the folder in question, enter into 'Security'?
In there, there should be an ownership tag, you'll have to add the administrator and remove all others. From there, do all your copying :)
Good luck, please report back on how it goes.
P.S. Possible google keywords: Windows XP Ownership Permissions Folders (Shudder at folders :P)