Dead battery won't recharge

security system was set off or battery is dead grab owners manual follow procedures to reset security system if this dose not work test battery if bad or low replace or recharge. also if battery is the issue be sure to have alternater tested for proper operation

replace a new battery.
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WiFi OBD device

Your battery is most likely dead if your lights go out. Charge or change your battery, but your altenater maybe be bad. It recharges your battery, if it don't work your battery will die..

u got a short or something.

You do not need to remove the battery to charge the battery. When you connect the charger you MUST be careful to connect the charger's positive lead to the positive terminal to the battery and the negative lead to the negative lead to the battery before you turn on the battery charger. Connecting the charger leads the wrong way around most likely damage the vehicle's electronics.
When you finish charging the battery turn off the charger before you disconnect the charger leads. This will prevent arcing between the leads and the battery.

"It won't do anything" means that there are no dash lights, no buzzers, nothing?
Any car has very slight electrical drains when it is shut off. For one thing, the clock is running, but there are a number of other tiny loads as well. With a good battery, you should be able to park a car for six months to a year and still start it.
However, if you start the car several times without running it long enough to recharge the battery, or if the drain is larger than it should be due to electrical problems or aftermarket accessories, you can get a failure to start.
Unfortunately, maintanence-free batteries don't tolerate being run completely dead very well, and many owners have unhappily found that draining an older battery once or twice was the last straw that ended their battery's life.
I suggest that you borrow a charger or a set of jumper cables to start the car, and drive it 30 minutes or so to fully charge the battery. If you have more problems, get the battery load tested at a shop that sells batteries to see if it is still OK.

It takes a special tool to reset the SRS on your MB. You can recharge battery as you normally would.

If ALL the windows quit working, then it's either a bad circuit breaker or a short circuit. There are two fuse/relay/breaker panels: under the hood and under the back seat cushion. The power window circuit breaker is under the back seat cushion, near the battery. Remove the back seat completely, then remove the fuse panel top and inner cover. The fuse diagram is inside the top cover. Circuit breaker # 57 is the one. Pull it out. Use your voltmeter/multi-tester to check for continuity through the breaker. If there's no continuity, the breaker is bad and needs to be replaced. If it's good, then you have a dead short somewhere that causes the self-resetting breaker to uncouple when you attempt to operate a window. If so, the short will need to be traced down and repaired. Good luck.

There is a hold down at the bottom near the battery,a 8 mm bolt head,or maybe a 10mm.

It sounds like you may a faulty door lock switch. If you pushed the switch to lock the doors and the switch stuck and kept door lock solenoids energized, that would drain the battery. It would also keep the door locks from unlocking, as to why window don't work it could all be on the same fuse or circuit breaker. Usually the power windows are on an automatic reset circuit breaker. Do you hear click and a short time later another click (with the battery charged)? If so that the circuit breaker tripping then resetting. Good luck!