I have an older Logitech G15 (blue LED's) that has had pretty much no problems in the past. The other day I noticed while playing an FPS that my backspace wasn't working. I tried looking around on google and got a few different things that could be wrong. I've tried to:
-Unplug keyboard and plug it back in on same USB slot.
-Unplug keyboard and plug it back in on different USB slot.
-Install latest drivers for the G15 (running XP).
-In Device Manager, uninstalling keyboard drivers and scanning for updates to reinstall them.
Not sure what else could be wrong. I'll keep fiddling around with it.