Some people call this rooting a server. Basically if you lost your root password and need to get int this is your only option. You will need to be in front for the server or with a KVN plugged in.
Make sure to follow each step exactly:
Reboot your computer / Turn your computer on.
Hold down the Shift key at the start of the boot process to enable the GNU GRUB boot menu (if it does not show)
Press ESC at the GNU GRUB prompt.
Press e for edit.
Use the Arrow keys to highlight the line that begins with kernel and press the e key.
Go to the very end of the line and add rw init=/bin/bash
Press Enter and then press b to boot your system.
Your system will boot up to a passwordless root shell.
Type in passwd yourusername
Set your new password.
Restart your system.