This morning I collected my repaired iMac 21.5 - after 3 months the hard drive had failed and was replaced. However, it won't accept my Password even though I know it's correct ! I can't change the password using System Preferences - Accounts as it will not accept my old password ! So, I need to use an Install disk to access info to enable a password change- apparently, the SAME disk that originally came with the machine. However, I am not sure which disk it is - I have a 10.5.6 disk labelled 2009 and a 10.6.4 disk labelled 2010. The machine says it's running 10.6.8, and I also bought a Snow Leopard Retail Disk 10.6.3. I have also read 'either use a disk which is closest to the current system' but also that unless I use the Exact Install disk version it can prevent me accessing my new account info' Any suggestions as to which disk I should use to set up new passwords etc ?