Kazaa Problem ???

Computer running Windows XP and problem started after someone recently downloaded the program Kazaa on a computer in the lab…

Now I can’t seem to REMOVE that program from the computer. Everytime I go to ADD/REMOVE programs and restart the computer the program appears back on the computer.

AND, I am unable to update the critical/security updates as well as any of the windows updates. When I go to install these updates, it appears to be installing them however, after I do the restart Kazaa reappears and none of the updates have applied.

HELP!! HELP!! I have no idea how this happened or what to do?

Thanks!