Another way to reset root password

You can reset the root password on any linux machine using this. For that you need to have a bootable distro like knoppix. Boot from the distro type linux single at boot prompt.
#vi /etc/passwd
Next, press the I key, which places the Vi editor in Insert mode. The first line of the passwd file looks like this
root:x:0:0:root:/root:/bin/bash
now carefully remove x from the middle donot touch: .After that it should look like
root::0:0:root:/root:/bin/bash
save the file by pressing esc key and typing ZZ
Now the next file open it using
#vi /etc/shadow
The first line is scrambled long characters. Change that to root:::: ie, root followed by four colons.
Save the file by pressing esc and typing ZZ
Now reboot the computer login as normal user.
Type
$su
#passwd
and change the root password as you want.