Password does not work after downgrading MacBook from Lion to Snow Leopard?

I downgraded my wife's MacBook from 10.7.3 to 10.6 i.e. from Lion to Snow Leopard. Lion was pathetically slow on her older version of MacBook.  Downgrade went smooth and I could restore the data from Time Machine as well. But after restore somehow the password of admin user was not working. Don't know why.  I […]