headlight problems

I have a 1997 Chevy 1500 4X4 with headlight problems. The truck has the daytime driving lights whish are on all the time. When I turn the switch to turn the headlights on the headlights go out. The parking lights are still on and all signals and brake lights work. To drive at night I've had to turn on the park lights and use them along with the Daytime driving lights but I have no high beams. Also when the lights are off with just the daytime lights on I have no high beam flash. It was suggested that I replace the on-off switch which I did but now I have no headlights or daytime driving at all. I put the old switch back in and still have no headlights or daytime driving lights. So I'm stuck with a new light switch thats usless. All the park lights and signals work. Any help would be great.