When the System Selection screen appears, use the up or down key to enter the selection screen.
Press "E" key on Red Hat Linux option,
Then there will be three options, press "E" key on "kernel/boot/vmlinuz-2.4.18-14 ro root=label=/" to edit
add "single" to "Ro" or "root" and return by return.
My approach is as follows:
"Kernel/boot/vmlinuz-2.4.18-14 single ro root=label=/"
Add "single" before "Ro Root"
Press "B" key to start, enter the character interface, when "sh-2.05b#" appears, it means that the single-user mode has been entered.
Now, enter "passwd root" to reset the root password.
After the setup is complete, reboot restarts, and the password you just set can be entered into the Linux system.
Extended Knowledge Reference:
Http://www.cnblogs.com/xiaofengkang/archive/2011/05/20/2052253.html
This article is from the "Flying Pig" blog, please be sure to keep this source http://thinkpig007.blog.51cto.com/971471/1435700