“database cannot be upgraded because it is read only or has read only files….”
1) Open Control Panel and run Services. Look for service named “SQL SERVER (SQL EXPRESS)” and stop it.
2) Double-click it and go to LOGON flap
3) You’ll se clicked “THIS ACCOUNT” pointing to that user. Click onto SYSTEM ACCOUNT, then OK
4) Star this service again
Sumber : http://social.msdn.microsoft.com/forums/en-US/sqlsetupandupgrade/thread/e75334af-ebbe-4663-8e9c-586a0aa025ac/