Do you know if it is HD44780 (Hitachi) compatible?
For the Parallel port, most set ECP but any mode will work.
To get info you need the right driver. A lot of LCDs are the Hitachi standard. If it isn't you will have to figure out what software will drive it (winamp plugins).
Now assuming that you have software (plugins) to drive it, I would double check the settings, including the contrast and brightness. And check the wiring.
If it is the Hitachi standard, I have a lot of links you can look at, otherwise I have nothing.