Hello and welcome to the forums.
Have you attempted to use the Windows Update Utility inorder to obtain a driver for your legacy printer?
Interestingly enough when I evoke the new driver wizard on my computer (Windows 7 Ultimate 64bit with Service Pack 1 installed), I find that Windows has native driver support for an
Epson EPL-5900 ("L") and a native driver for an
Epson EPL-6100L (which may work)
I have searched and haven't found any other resource for Vista or Windows 7 for Drivers for your printer.
Evidently the printer has a Parallel as well as a USB interface for connections to your computer. Have you tried both or is that not an option?
As far as I know, that USB port is generally a good default, with the only caveat being if another device is or had been using that same port. I've attached a screenshot of mine which is as you have indicated seems to be the same as you are using.
Also sometimes these types of cables can be unique and proprietary. Do you know if it uses a generic USB printer cable, or do you suspect that it is somehow a special cable?