Recover Password Of --> Linux Ubuntu , Windows XP, Windows Vista ,Windows 7

Sometimes it happens that i forget my password.. what to do ??? here i will show you two ways for different OS (linux Ubuntu 
and Windows XP ) 

1) Linux: 

1. Reboot your computer and when you see GRUB Loading Screen press ESC so you come into the menu. 
2. Now choose recovery mode 
3. Chosse root shell prompt 
4. now the system will show you cmd 
to reset your pass use "passwd" 
5. if you are finish with that reboot your system 
command : reboot-f 

2 ) Linux 

1) choose the regular boot 
2) use "e" to edit the settings 
3) now hit the arrow key down over options and then use "e" to change to the edit mode 
4) ok now you will get a scree with "single" 
5) remove single with delete key and add this : rw init=/bin/bash 
6) ok use "B" to boot with this settings 
7) and now you get cmd and you can use the things I told you with the other method 

3) Windows versions 

Its always the same way you only need to download the right Ophcrack version for you operating system. 
1. download ImgBurn here 
2. Download Ophcrack : XP Windows Vista, 7 
3) now burn Ophcrack with ImgBurn on a dvd 
4) start your pc and do the dvd into it 
5) open bios and choose boot from dvd 
6) it will take 5 minutes but then you will get all Users from this pc and their passwords