Mercedes: 1994 mercedes 500sl wont start, mercedes 500sl, starter solenoid

Question
My 500 SL won't even try to start even though the battery is ok .I stopped the car for a miniute , went to the bank ,used my key to lock the money in dash compartment, and when I tried to start it the key turns but nothing happens . Is there some kind of switch or something that won't unlock starter?  

Answer
Terry,
If the vehicle has a security alarm, it may be tied into an ignition kill circuit.
There may a fuse burned. Check all the fuses.
The ignition switch may have failed.
The starter solenoid may have failed.
There may be a ground /corrosion fault in the start circuit.
The fuse link in the main supply line may have failed.
Do all the electrical accessories work?
If not which ones are not working?
Have you had any other things happened that may have indicated this may be a possible happening.
Rob