I have an Acer 24" LCD (model "AL2423WDR") that's about 3 years old. It worked perfectly for most of its lifetime so far.

Recently it started giving problems. When I turn it on, it either says "no signal" on the display, or the power light goes yellow (as if in power-saving mode). This happens with both DVI and VGA (both of which worked fine before), and stranger still, the 4 buttons on the front, for accessing the on-screen menus, don't do anything. I've also tried different computer hardware and software (PC/Mac, Linux/MacOS), but nothing has worked.

I've tried power-cycling it (with both the power button and the power switch), and also unplugging it entirely.

The nonworking buttons suggest to me an issue with the firmware. I found a place on Acer's website that says I can send it in to have it fixed, at my expense, but I'll avoid that if I can. Is there a way to fully reset it manually? Or is there something else I can try?