Forgotten root Password (Linux)
You can log in using single-user mode and create a new root password.
1. At the boot loader menu, use the arrow keys to highlight the installation
you want to edit and type [A] to enter into append mode.
2. You are presented with a prompt that looks similar to the following:
grub append> ro root=LABEL=/
3. Press the Spacebar once to add a blank space,
then add the word single to tell GRUB to boot into single-user Linux mode.
The result should look like the following:
ro root=LABEL=/ single
4. Press [Enter] and GRUB will boot single-user Linux mode.
After it finishes loading, you will be presented with a shell prompt similar to the following:
sh-2.05b#
5. You can now change the root password by typing
passwd root
6. Reboot by typing reboot at the prompt;
7. You can log in to root as you normally would.