Ubuntu
1) When boot loader Grub (particular place where You select different OS )start
Select Failsafe in Ubuntu
Or
Select Ubuntu press e For Edit The Ubuntu Entry
Add "single" At Last When Kernel Location Define in grub Like
linux /boot/vmlinuz-2.6.38-8-generic
root=UUID************** ro quiet splash vt.handoff=7 single
press F10 or ctr+x
2) Select Root Option
3) Now You are root user
sh#
4) use passwd coomand to change password for particular user
sh# passed <username>
5)reboot
Fedora
1) when grub loader loaded select fedora Option press e
add 2 after kernel option define in grub list and change the passwd
so to please put password on grub so unwanted user can't change your password
1) When boot loader Grub (particular place where You select different OS )start
Select Failsafe in Ubuntu
Or
Select Ubuntu press e For Edit The Ubuntu Entry
Add "single" At Last When Kernel Location Define in grub Like
linux /boot/vmlinuz-2.6.38-8-generic
root=UUID************** ro quiet splash vt.handoff=7 single
press F10 or ctr+x
2) Select Root Option
3) Now You are root user
sh#
4) use passwd coomand to change password for particular user
sh# passed <username>
5)reboot
Fedora
1) when grub loader loaded select fedora Option press e
add 2 after kernel option define in grub list and change the passwd
so to please put password on grub so unwanted user can't change your password
