Exactly what do you mean by" owner account"?
The account is either Administrate or Limited.
You can make your folders private if you use NTFS and not FAT 32 file
system.
And disable Simple File Sharing (Windows XP Pro)
For Windows XP Home, you need to go to Safe Mode. http://www3.telus.net/dandemar/private.htm
If the other account is also Administrator, this will not keep access from
that account since any Administrator can do and undo anything any other
Administrator can do.