A couple years ago i used my macbook for school and they installed their own administrative account, so i had 2 accounts, one for them and one for me, and i was always able to install updates and my username and password always worked until now. i realized that their administrative account is gone and somehow got deleted! Now every time i go to install something my username and password doesn't work, and I'm 110% sure its the correct combo. What do i do????? i cant access anything! i have everything backed up in time machine on an external, if i put my restore disk in will i loose leopard, cause that was installed after i bought my mac, and how do i re-install everything from my backup?