Try tapping the statrer motor with a hammer handle osimilar piece of wood.

If it starts you have a possible couple of problems with the starter.

Either the voltage is dropping and the solenoid is not kicking in, the brushes may be worn (less likely)

A simple fix is to fit a relay at the starter motor (or have one fitted)

This usually cure most starting worries and is not an expensive repair 

To change a syncromesh ring on any gearbox requires a fairly major strip down.

Unless you have either done one before or can follow a workshop manual "LET AN EXPERT DO IT"

You didn't say if the starter motor clicked when you turned the key.

However if it happens when the car/engine is hot, get an auto electrician to fit solenoid close to the starter motor.

This wil cure almost all poor starting worries and it is not an expensive repair

Support the motor and desconnect the trim ram from the engine.

Test the trim motor and ram action whilst it is disconnected.

This will tell you if the ram or motor is seized.

If the trim ram is working then you need to look at the main engine pivot point

First and foremost make sure you know which is "Earth"

Then depending on what you are going to run the other three wires will go int the rest of the terminals

If you are running an electric motor or pump etc. just jog it and seee if it is turning in the correct direction.

if it is not, swith any "two" (except earth) of the cables and it will turn in the right direction

I had the same problem, took safe to locksmith and he got it open without much problem

Take it to a dealer. The light is there for a good reason