I'm not familiar with Media Center Edition but you might try logging on as an admin, right clicking the start button and choosing Explore All Users. R-click the profile and select Sharing and Security, then the Security Tab and Advanced button. Click the Owner tab and take ownership of the folder. Also check the box, "Replace owner on subcontainers and objects." If this isn't possible for Media Center Edition, try from safe mode using the admin account.
i just installed win xp media center......... now my old profile made private by ticking make folder private option under ntfs system cannot be accessed nor deleted and it is comsuming about 3 gb of my 40 gb harddisk ...plz can some one help