Zaurus ZR-5800 Screen remains blank

I have a factory reconditioned Zaurus ZR-5800 which is a spare in case my other unit stops working, so it has had almost no use since having been reconditioned. However, I have kept it installed with good batteries, and I turned it on every once in a while. My problem is that last time I tried to turn it on, the screen remained blank. The touch screen and keyboard still beeped when touched, and the backlight works, but the screen remains blank. I tried changing the batteries and I tried changing the brightness on the screen using the keyboard, with no luck. Any suggestions?