If you are using windows vista and having the service temporarily unavailable error code 80070005 when signning in to msn, most probably is cause by the permission problem (bear in mind that for some the error code may be the same, but the cause of the problem could be different.)
Try the following method to solve the problem (for those who set a password on the pc):
1. Close Msn completely (make sure is exit completely)
2. Go to Start --> control panel --> user accounts
3. Remove the password of your account
4. Open Msn and sign in (you should be able to sign in).
5. Go to Start --> control panel --> user accounts and set password again (Don't sign out msn, make sure msn is signed in when you set the password.