avensis wont even try and start

[plfclf]

got a 2000 w toyota avensis and have been having problems starting it until one day when it wouldnt even try.
called out services and they set me up with a temporary lead from my starter to dab on to the battery to start the car as there was no feed getting to the starter.
speaking to a work mate about this he said that it may be an immobilisor or solenoid between the ignition and the starter which is prob faulty, if this is the case how do i find it and repair it?

[chadad]

I had the same trouble with a ford escort.
I made a temporary repair by fastening a strip of metal to the power cable nut on the starter ( Thick lead )
To start the engine I just had to press this to contact the solenoid connection (thin lead ).
The fault was a worn out starter switch. (Old age )
And was fixed with a replacement from the local breakers.
Cost, two quid.
N.B. You only need to replace the connection on the starter switch, not the entire lock.
Hope this helps.
chadad