Celeron 300/PC Chips M747 MB won’t communicate with Cannon 7000 printer. Bi cable/parallel port OK. LPT1/ECP/EPP tried. Reinstalled updated drivers. No apparent irq conflicts. Won’t print in DOS. Does work with one HD from previous install, not others. Cannon monitor program say’s “port is being used by another device.” ???? Any suggestions on what to do next? Thank you.