> volume license key has been blocked
If you work for an organization that has licensed, in "bulk", copies of Microsoft Windows, then your I.T. department would have received a "volume" license-key, i.e., one license-key spanning _every_ licensed computer, not one unique license-key _per_ every computer. If so, contact your local I.T. department, and ask them why Microsoft is now "blocking" usage of computers that are using that "volume" license-key.
Or, if you are using a "bootleg" copy of Windows XP, i.e., somebody outside of the organization that licensed that "volume" license-key has ILLEGALLY used that license-key to install Windows on your computer, then you need to purchase license of a "genuine" copy of Windows XP.
for details on how to "get genuine".