1999 malibu, engine turns, won't start, guages not

I would recommend looking closely at your illumination circuit. There is a gray wire that if shorted could prevent the digital guages from displaying. I would look at the radio connections, especially if you have an aftermarket radio. Also, look around the lighter and maybe a bad dimmer switch.
To trace the problem with the horn fuse, look for shorts in the orange wire. Common places are around the radio or the screws that secure the panels under the dash (floor lights on the dome circuit).
As far as the no start, sound like old and dirty terminals and/or cables.

sometimes the radio is programmed as an alarm. unhook the radio to see if the program is causing your problem.

check the ground leg to your engine.. it runs off the neg. battery terminal. will connect to frame and engine.. pull it off, wire brush it put it back.. you radio will work, 'cause it draws much less current, and is grounded in dash.

Does this sound like an electrical problem !!!!

You said you got no power,lights,doesn't start,
& more,what do you think

Have you checked the battery?
Do you know how old it is?
Have you checked for codes?
Have you done anything,call a repair shop?

probrably body control module going out its located bottom passenger side of dash by the blower

ignition switch contact or starter motor given up the ghost ,try a jump start and see if that works ,do the lights go dim when you try to start it??if so then its a flat battery or a old battery thats just died on you.These vehicles do have a big ignition lock in the dash and these just dont go wrong like a VW but its possible?

The security system does not disable the starter, it only disables fuel to the engine. In the fuse block under the hood, locate the STARTER relay. Place your hand on this relay and see if it clicks while someone else turns the key to start...if the relay is ok then the starter itself is faulty. Good luck, i hope this helps.

Check your fuses. The dash lights are on a different fuse. Also check dimmer switch. If its not one, then it is the other. Try working dimmer switch quickly back and forth( with the lights on when it's dark so you can see if they come on).

For general awareness, the outside air temperature sensor is located above the inside mirror.
Try to reset the temperature measurement unit: 1. Switch engine on. 2. Press and hold clock minute (min) and hour (h) buttons simultaneoutly longer than 3 seconds. The display will show new temperature measurement unit. 

Does the dash gauges and digital mileage and idiot lights work when you turn the key on?