You will encounter all sorts of these problems unless you do things properly. Before you sell or give away a Mac, use its original System Install DVD and erase the disk. Then, reinstall OS X. When you get to the new owner setup procedure, just shut down the Mac. Its new owner will take it from there.
Give him your System and Applications Install DVDs. These must always accompany a Mac unless it was built with Lion or Mountain Lion already installed from the factory.