Linuxcentos root password solution

GRUB: on the boot loader menu, type [e] to enter the editing mode. You will face a list of pilot projects. Find the line with the output similar to the following: kernel/vmlinuz-2.4.18-0.4roroot/dev/hda2 press the arrow key until the line is highlighted and then press [e]. You can leave one blank at the end of the text.

GRUB: on the boot loader menu, type [e] to enter the editing mode.
You will face a list of pilot projects. Find the following output sentence lines:
Kernel/vmlinuz-2.4.18-0.4 ro root =/dev/hda2

Press the arrow keys until the line is highlighted and then press [e].
Now you can add a single entry at the end of the text to tell GRUB to guide the Linux mode of a single user. Press [Enter ].
Make the editing result take effect.
You will be taken with the edit mode screen. From Here, Press [B] and GRUB will guide the single-user Linux mode. After loading, you
A shell prompt similar to the following is displayed:
Sh-2.05 #

Now, you can change the root command and type:

Bash # passwd root
You will be asked to retype the password for verification. The password will be changed. you can enter reboot at the prompt to re-import
Then, log on as the root user as usual.

LILO: when the system starts to display the LILO boot screen, press TAB for the graphic boot mode to enter the text mode, and then click
Location

Enter linux single press enter to enter the password-free console, and then use the passwd command to change the root password
You can.