After jump starting c240 and drove arround it wont engage reverse and now wont start

The battery may be flat. Read the manual on using jumper leads and try again. Also check for proper contact between the battery p[ole and the cable, positive and negative.

HI,THAT IS A USUAL ISSUE RELATED TO THE ELECTROMAGNET WHICH IS ENGAGED ON "P or N" position.Charge your battery overnight,try your handbrakes,if they work fine,just leave the car in whenever you stop and put your handbrake on.This won discharge then the battery unless there is a unrelated electrical fault in the system.

Dangerous practice to try & jump a near dead battery

Always try charging a battery, that is only a couple years
old & not run down more than two or three times

If the battery is dead & reads less than 12 volts, have a parts
store test it or just replace it.

Jumping a cars battery is not a fix for anything,so I fail to
see how your lost & have not addressed the battery issue,
so you can continue on with other testing,if needed

Is the starter engaging when you jump start it? You say you replaced the battery, is the cable ends clean? If the starter is engaging you have other problems, if its not then check out the starter/cables. Good luck!

The clicking sound is the starter motor trying to engage, but does not engage because of low electrical current. Knowing that you started your motor with jump leads this morning indicates that your car's battery needs charging/replacement.
Hope this helps.

My Mercedes C-Class 1996 won't start up, the alarm is confused it thinks it's locked, every time i unlock it, the red light( locked) and green light(unlocked) flash at the same time constantly, if I open the car and try turn on the engine, the alarm starts blaring, I've turned it on before and drove it around but when i came to park it up it did not turn on again because of that problem.( The car hasn't been touched or used for a year before i got it going again)

Remove the lugs at the battery. Clean the posts and the lugs - then reconnect. Your battery won't charge (and the jumpers won't work) largely because of a film on the + post and lug. If you live in a hot summer area, (Arizona) the problem is especially troublesome.

You need to set the parking brake, Turn the key on let it sit like that for 10 mins. the sec light will either start flashing or will stay on or go off when done (This will reset)
REPEAT 3 times!
Then you should be able to start the car after the 3rd time!