vectra 2.2 diesel problem?

it all started with my immobilsor not being able to turn off with the remote key, then it was a steering wheel light with an exclamation mark through it coming on and off, then the traction control light coming on, then battery light coming on and off, then a car with a spanner coming on and off, then no rev counter, diesel guage or speedometer working, then sometimes when try to turn the ignition on i get nothing then all of the sudden the car will fire up as if by magic, i took it vauxhall garage and they couldnt diagnose the problem, they said i needed a new battery then was told i may need a new sim module and then told i may need a wiring loom for something so still none the wiser can anybody help, i was also told it was the baro pressure sensor but its definatly not all those things, i was even told it was faulty earths and had all of them done , still no good after that.. er any answers any one please?