How can I reset my iMac?

Episode 1278 (37:21)

Donald from Mojave Valley, AZ
Apple iMac

Donald has an iMac and has to have his screen repaired. But he doesn't know how to wipe the drive since there's no command key. Leo says that Apple has changed it from CMD to an Apple Key and a cloverleaf/propeller symbol. It's the same. How can he reset his iMac and wipe the drive if he doesn't know the password? Leo says to reboot and while it's starting up, press the CMD Key, plus R. This will put the computer into recovery mode and he can then run the Disk Utility to format the hard drive. Then he can reinstall.