2000 s500 will not start,but key turn

Does it click or do anything? If not, then the plastic gears inside the ignition that control the vehicles ACC and ON positions along with the cranking may have slipped. Have someone to pull the ignition switch panel and check and make sure the "gears" are working properly.

have you checked coils,or coil fuse,possible bad maf sensor

the anti theft may have lost its memory you will have to have it looked at.by dealer.

listen for the fuel pump when you first turn the key if you don^t hear it ? start there .

Well try changing the battery and see if that helps your situation, if not then id start with a full tune up and go from there. Im sure a new fuel filter wouldent hurt either.

tune up

Steering wheel is 'locked' - move it left or right while trying the key. Or make sure the gear selector is fully in Park, if an Automatic.

It's not that unusual for a battery to fail that soon, and the "no lights, no nothing" says that it's the battery again. Your best bet at this point is to pull the battery and take it to the point of purchase for testing. They should either replace it under warranty or charge it for you. After you replace the battery you should have the charging/electrical system checked for possible shorts or power drains.
BillB

Malfunctioning fuel system.
Fuel injector[s] leaking...check fuel pressure,more then 53psi
check fuel injector resistance / ohms/
Ignition component damp or demaged.Checks wires broken,loose or disconnected in the starting circuit.Worn, faulty spark plugs.....

Check Battery in car(make sure is not weak or dying), check battery in remote fob, possiable draw in system possiable fuse or possiable keyless entry module failure