No idea how to do it on an Air, but here's the normal way...
1. Insert the Mac OS X Install disc, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Reset Password from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Reset Password.
I have the same password problem. Twice now I have restarted with the C key using the Install disc, and reset the password. On both occasions when I came to go back into my user area, the password was not accepted. It gave me the correct hint, but would not accept the password.
So where do I go now? I am effectively locked out of the computer and all its files.
Here's the instructions if you have the discs.
*Mac OS X: Changing or resetting an account password*
Try this (OS 10.5 only). *How to Reset User Password via single user mode*
I tried the second option, through the Command S route and changed the password, but
it still was not accepted.
By the first route, if I try to unlock the authentification lock in Apple user mode, it asks for a password there, and I have no idea what that is. And when I have previously tried the change password route in Accounts, it has asked for the old password before the new one, which of course I cannot give as it is not being accepted.
Thank you all.. Tom - I tried the 2nd option (bc I dont have the start up disk and Im on an air so no place to put the disk into) and it didnt work... I typed in all the words you told me but it was unsuccessful.. Do I pause between the different computer comments like "checking... server" and so on - I got a few of those..
Thanks again - I would LOVE to fix this wo having to spend money on help.. Rachel