Beating my Head Against Antique Computer Wall.

The Dell Optiplex 960 that controls my mill is an antique.  I have been trying to upgrade to the latest version of LinuxCNC, but that requires an AMD64 processor or equivalent.   This Dell is a 686 processor which doubtless explains the bizarre problems with upgrade.  I do not need fast or powerful for this.  As long as I can install a Centronics parallel port in it I am good.  I should be able to buy something used, cheap, and with a tiny footprint for this.