HP LaserJet 1100 problem

I’m having bit of trouble with my HP 1100.
My HP 1100 is feeding papers constantly as soon as Window XP is logged on and prints out one line of garbage characters at the top.
I would reset the printer and it would stop as long as the computer is off. But as soon as I boot it up and I log on to the Win XP, it will kick off the printer again.
Any thoughts? Would really appreciate your feed back..
(Printer is connected local via parallel cable.)