Marylpf,
As you mentioned you have tired several possible solutions and from the looks of it all the suggestions we could think of. In addition to what you have tried make sure your BIOS has the parallel port enabled or LPT1 enabled, we have had several issues where the port mode was properly set but the parallel port was disabled. Additionally we would like to know is your computer running Windows XP? We have read several posts about this printer working fine until the user upgraded to Windows XP and are concerned that maybe your issue is incompatibility with the printer and Windows XP (even though you are using Windows XP drivers).
Although it is possible that your computer or the printer may be defective, without trying the printer on another computer and/or trying another parallel device on the computer we cannot say for certainty. If you have another parallel device that you could connect to the computer to make sure the computer is working or if you could try the printer on another computer preferably a non Windows XP computer this would help determine if you are unable to resolve the issue because of a hardware defect.