Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
The saved password ***** safari would be stored in your keychain, since you moved the hard drive to another mac, it probably wont work if you were planning on just opening safari and signing in.
Also, if safari ever failed, youd be without your passwords. So it may be best if you and I discuss what email addresses or accounts that you need the saved passwords for , and then if we manually try and recovery and set new passwords for those accounts.
If I have misunderstood what you are trying to do, please send a response and clarify the issue.