See Help and Support and search for "take ownership"
HOW TO: Take Ownership of a File or Folder in Windows XP
http://support.microsoft.com/?id=308421
Then once you have ownership, assign rights to other user.
XP Home: By default, you can only make files and folders under My Documents "private". This is done by right clicking a folder or file and selecting Properties, Sharing. To change the permissions on other folders, you need to boot the computer to Safe Mode and log in on the built in Administrator account. In this mode, you'll see the Security tab in Properties, and you can assign permissions based on user name or group membership.
How Do I Get the Security Tab in Properties - XP Home (makes the Security tab appear outside of Safe Mode)
http://www.dougknox.com, Win XP Tips section
HOW TO: Set, View, Change, or Remove File and Folder Permissions in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;308418
HOW TO: Set, View, Change, or Remove Special Permissions for Files and Folders
http://support.microsoft.com/default.aspx?scid=kb;EN-US;308419
HOW TO: Disable Simplified Sharing and Password-Protect a Shared Folder in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;EN-US;307874

Signature
Doug Knox, MS-MVP Windows XP/ Windows Smart Display
Win 95/98/Me/XP Tweaks and Fixes
http://www.dougknox.com
--------------------------------
Per user Group Policy Restrictions for XP Home and XP Pro
http://www.dougknox.com/xp/utils/xp_securityconsole.htm
--------------------------------
Please reply only to the newsgroup so all may benefit.
Unsolicited e-mail is not answered.
> I am running WIN XP Home with 2 accounts set up as
> admins. No problems til recently, now files and folders
[quoted text clipped - 4 lines]
> access as the other admin account? Should I delete the
> bad admin account and recreate it? Thanks.