If you forget the admin password than don't worry. I have some easy trick to recover your admin password without using third party software. this is a loophole in Windows XP Setup and a big security hole:
A. Boot using Windows XP Setup CD and follow the instruction like Accepting EULA, etc.
B. When it asks to repair your existing windows installation, accept it and press "R" to run the repair.
C. Setup will start repairing your Windows and will start copying files, etc.
D. After a few minutes setup will restart your system and when it restarts don't press any key when it shows "Press any key to continue..." otherwise Setup will start from the beginning. Don't press any key and setup will resume where it left.
E. Now it'll start doing other tasks and will show a small progressbar with a few details in left side.
F. Once the computer starts back up it will jump into the installer. Here, when you get to about 37 minutes left on the installer it will say Installing Devices on the bottom left hand side of the screen – Hit Shift-F10 at the same time and a command prompt will pop-up! Just like that..
G. It'll open a Command Prompt window. Now type nusrmgr.cpl and press.
H. It'll open the same "User Accounts" window which you see in Control Panel.
I. Now you can remove or reset any account password without any problem.
A. Boot using Windows XP Setup CD and follow the instruction like Accepting EULA, etc.
B. When it asks to repair your existing windows installation, accept it and press "R" to run the repair.
C. Setup will start repairing your Windows and will start copying files, etc.
D. After a few minutes setup will restart your system and when it restarts don't press any key when it shows "Press any key to continue..." otherwise Setup will start from the beginning. Don't press any key and setup will resume where it left.
E. Now it'll start doing other tasks and will show a small progressbar with a few details in left side.
F. Once the computer starts back up it will jump into the installer. Here, when you get to about 37 minutes left on the installer it will say Installing Devices on the bottom left hand side of the screen – Hit Shift-F10 at the same time and a command prompt will pop-up! Just like that..
G. It'll open a Command Prompt window. Now type nusrmgr.cpl and press
H. It'll open the same "User Accounts" window which you see in Control Panel.
I. Now you can remove or reset any account password without any problem.