Start your netbook, laptop or pc with a install Ubuntu CD or Memory USB Drive
Select option to try Ubuntu
Once booted go into the Terminal
CTRL+ALT+T
Some or all of the commands below made need to be carried out as root using sudo:-
mkdir p
mount -t auto {DRIVETOMOUNT} p
e.g. mount -t auto /dev/sda2 p
{Then chroot to that mounted partition}
chroot p
cd /boot/grub
chmod 777 menu.lst
{use gedit ot vi to edit menu.lst}
{comment out hidden}
# hidden
{set timeout value in seconds}
timeout 30
{exit from editor}
update-grub
{to reboot type}
reboot
During Reboot Select recovery mode
This should Logon to root
type passwd {username}
e.g passwd peter
{Enter the new password}
reboot and use the new password