My wife's laptop updated last night and it's asking her for her password.
She can't remember it. She entered a password hint, but that's not jogging her memory.
Is the only remedy for this some kind of backup disc?
Try this utility. It will let you boot onto a reset boot disc, and change the password.
Please note that the utility does mock with the registry in an undocumented way - it should be safe, but I would recommend that you backup the disc first. As already answered, remember that this trick will render any encrypted files useless - it that feature has not been used; this should be a fine way to do it.
Did you create a windows password reset disk? Of course, Encrypted files will be lost if you use any PW reset utility.