What are you doing if your computer password lost?
You lost your root password, and need to get into your root Account?
This is something-serious well we'll try to work something out.
You need to have physical access to the Server or computer.
What you will need to do, is a re-boot.

Ok, Now how do you do it.

1: First think up a new password.

2: Reboot the machine.

3: At lilo prompt type Linux 1 This will bring up a single user system.
The prompt will be something like: #

4: At the prompt after you are in type:
passwd root

5: Enter your new password at the prompts.

6: Reboot like normal This reboot will return the machine back to normal run levels.

or if you don't want to reboot, type one of the following:

init 3 (for console login, which is the default)
init 5 (for XDM login)