Kempus,
An adminstrator may be "locked out" of folders, but can actually reset the permissions on them by "taking ownership".
This is a design feature of NTFS, such that users can prevent admins from viewing sensitive information - and if the admin does exercise his "divine rights", there is an audit trail (muddy size 10 footprints).
Right click the folder, select Sharing and Security, Security tab, then drill down into Advanced and you should find Owner tab.
That's for Windows XP Pro - if you are using XP home you may have to turn off "simple file sharing" or something like that. Win2K is as above - as was NT4 and 3.51 was similar.
Of course if you had encrypted the folder or files using built-in or 3rd party tools you are f***ed!
SD