forgot administrator password

Scenario:

I forgot my password for Windows XP. There is another account on the computer. I do not have the Windows XP disk. How do I change the password or just get into the administrator account to change it there??????????????

Only the so-called 'administrator,' or an account created with administrator-rights, has the ability to change any account password. The key to changing the password, however, is that you know what it is. Windows documentation has cautioned (repeatedly), that, if you create a password, you should write it down and keep it where you can find it later, not necessarily 'on your computer.' Even though we live in a so-called paper-less age, there is still a use -- besides wiping your butt -- for paper.

Your story sounds just a little tiny bit implausible....

If the other account on the device has administrative rights, you can delete the administrator account and create a new one, if you wanted one. But, why would you need another, if it is your computer?