It's not difficult. But you need a XP bootable CD, and follow the steps below.
1.) Place your Windows XP CD in your cd-rom and start your computer.
2.) Boot from CD using “Press any key to boot from cd” option at startup.
3.) Now the setup is inspecting your system and loading required files.
4.) Press ENTER to Setup Windows now. Then accept the Lichening Agreement by pressing F8.
5.) On the next screen gives you the option to do a Repair. You will notice it like a phrase “If one of the following Windows XP installations is damaged, Setup can try to repair it”
6.) Press R to begin the repair.
7.) Let the Repair run. Setup will now check your disks and then start copying files.
8.) Your computer will reboot.
9.) During the reboot, do not make the mistake of “pressing any key”. The system will reboot again.
10.) Keep your eye on the lower left hand side of the screen and when you see the Installing Devices progress bar, press SHIFT + F10.
11.) At the prompt, type NUSRMGR.CPL and press Enter. You have just gained graphical access to your User Accounts in the Control Panel.
12.) Now simply pick the account you need to change and remove or change your password as you prefer.
13.) Once the Repair is done, you will be able to log on with your new password.
I think I'm clear for you.
