Printer LPT1 in PC- WinNT does not print

Hi there,
I have a PC with Windows NT Workstation 4.0 and a printer connected to the LPT1 Parallel port,the HP720C does not print,swopped Parallel cable,Printer and Re-installed Driver,tested parallel port with external loopback plug with the aid of a diagnostic program-tested OK,checked BIOS OK,prints only to printers on Network.
Can you guys help me out,what solution?
Ceasar