GPS & Alt. Pressure

I'm in the middle of a flight an for some reason I reloaded my IFR and the GPS starts over from where I took off. Is there a way to change which leg I'm flying on the GPS? Also, I haven't been able to figure out how to change pressure from 29.92 to anything else. I assume each plane is different. Right now I'm in the POSky 777-200 and I don't know how to change it. Speaking of the 777-200, has anyone else had trouble getting the inside cockpit lights to stay one? When I turn the lights on they flash on but then they don't stay on except in maybe certain places. Any ideas? Thanks!