Encrypted PST – Error 5: Access is denied

I have a user that was migrated from peer to peer to a domain network. The workstation is running Windows XP SVC2 and MS Outlook 2003. After the network migration the users old pst file wouldn’t open and now says Error 5: Access is denied. I reapplied administrator settings and verified that read only is not checked but receive same error. It looks like that somehow the user ended up with an encrypted pst file and it will not allow me to uncheck the encryption nor make a move the file. Is there a way to regain access to this file?