When you squeeze the torch trigger, three things should happen:
1 - wirefeed motor starts
2 - contactor ( heavy-duty relay ) closes, powering-up the arc transformer
3 - gas valve closes
I assume that 1 is OK, but 2 and 3 are not happening? You should be able to hear the contactor close, and maybe hear or feel the solenoid of the gas valve moving.
Both the contactor and the gas valve are switched by the same relay on the control printed circuit board, so it may be faulty or not getting actuated by the logic on the board. There is a second relay on the board that switches on the wirefeed motor.
The contactor has a plastic button in the centre of the top, which allows the contacts to be closed manually.
**Note that the wires in that area are carrying live AC mains !!
With the machine powered up and the torch trigger pressed ( or taped shut ), use an insulated screwdriver to push the contactor manual button, and check if you can strike an arc.