My key isn't working to open my door could the battery be dead?

Check the battery voltage, it should be 13.5 V, kick the headlights on for a minute and see if this "load test" will be sufficient to crank it over.

...else throw a charger on it for eight to ten hours, I'll be expecting a full report, in the morning!

Check the battery in your remote control while you have your meter out.

THE KEY MIGHT HAVE LOST ITS CODING THAT CAN HAPPEN BUT CHECK BATTERY IN ROMOTE

you know modern car batteries will stop taking a charge ten percent per year....so check the "knock-off" labels on the top of your battery to see how old that it is...buy a new battery~

Why cant i open the doors with my key on my 1995 c280 mercedes