Cracking Windows XP

Cracking Windows means 2 things
1>cracking the password without knowing the original password
2>Somehow Knowing the password and then using that password without letting the user know

cracking password
In XP we generally deal with 2 types of account.
Administrator Account
User Account

When XP is loaded in a computer,it asks for administrator password,generally people keep   it blank(So that  pasword can be reset when we forget later and Most of the time,people dont use their Administrator account,they like to work with   their user account.

This is how you can  crack their PC and hack Administrator Password

1. Start your computer 
2. It will take you to logon screen.where only user Account is visible, 
3. Press Alt+Ctrl+Delete (2 times).it will take you to old NT style logon box 
4. On username:  administrator   
5. Password:                    press Enter     
6. System will login using administrator account.
7. Now from ur Administrator account,Open command prompt
8.     Start-->run-->type "cmd"  without space
9. In that command Prompt or DOS screen. Type   net   user  administrator   *        press enter
10. It will ask for password.Press Enter 2 times and it will say command completed successfully
11. Now you have sucessfully cracked users Password,without knowing existing password

This is not a hacking,windows had given u feature,thats why u could do it.

File where your XP accounts and passwords are stored

In windows xp,when ever we login,we have to provide a userid and password.The system will then try to match this parameter from a file where it has stored account info.So which is that file is the main Question?
c:\windows\system32\config\ SAM
Yes,SAM file contains the information.But we cannot copy and export or delete that file,it will show you the file is being accessed by some other process.System process is running behind the screen and it doesnot allows you to copy,delete or modify.
Even you cannot kill the system process,if u try to do ,you will get a system shutdown message with in a minute.and your system will be shutdown within 1 min(type shutdown -a in dos prompt to abort shutdown)

So can we know the password of the user.Yes we can use a tool called SAM Inside which can use BruteForce and Dictionary attack to get the password for us.
Dont try to copy SAM from Dos safe mode.still it will show you same message.

Good Luck