Could be a hardware failure or MCU onboard the serial display stuck on a strange state.
I have seem mostly sparkfun serial displays being mentioned on this forum.
Maybe get one of those. Or, maybe, get one phi-panel after you get back. The serial phi-panel has 20X4 display, 0-9 keys, directional keys, enter and esc, 4 LEDs, 4 general outputs, a buzzer that can plan any tone, everything controlled by Serial.print more or less ANSI sequences, and option to power itself with voltage regulator and ac adapter. Making a menu with this panel is a snap since you can just Serial.read() the user key presses and Serial.print standard ASCII with ANSI control sequence to control the display. There will be multi-tap inputs over the number pad but I'm still working on the code. I'll post some updates so just keep an eye for phi-panel 
Here is a sneak preview:
