1997 Pontiac Firebird Problems with dashboard lights and he

I bought a very nice 97 automatic V-6 Firebird coupe that I am using to commute with. Recently it began exhibiting some straneg intermittant problems that I am unsure wht to make of. Several times the "Please Service Engine Soon" light came on and then later (after several days) went out again. Then the lighting that comes on when you stop the engine and open the door to leave starting fading on and off when I first started the car. Most recently the dashboard will suddenly light up while I am driving and every light will flash on and off, and then it retuirns to normal, except the time on the radio resets and the trip odometer zeroizes itself. Now the headlamps will not pop up if I turn on the switch for them. Where should I look to find the problem?

Barry