1996 Chevy Lumina 3.1 sedan overheated and now has no electrical power at all. How do I fix it?

You've overheated. This means it's boiled dry. You have to replace the missing coolant and figure out why did it overheat? No electrical power? the battery got comprimized, or simply isn't solidly connected. A load tester (your local mechanic has them) would tell you the health of this battery, but probably the battery terminals are corroded and good juice can't get thru (amperage, y'know)...barring your battery, does it still crank over and start?

that hose came loose for a reason...probably the reason is "I'm old now, and need to be replaced"~

Ed777 doesn't seem to excel at communication skills...o boy, left out here with our union suits undone~

...whatever... it's still fun to have food for thought... ...I had a '91 Pontiac Sunbird convertible, 3.1/V6... One big mambojambo fusible link down by the starter went Bad..... but before it went completely bad..... it was "iffy" bad..... I'd be driving along, and then suddenly, "black out"..... once right in my drive way..... the next morning, started right up..... the a couple more times similar..... then a coworker tipped me off about the Fusible Link, and that one could be "not completely bad".... sure enough, after cleaning off all the junk and guts.... one of the links looked a bit more brown and a little bit misshapen than the others.... apparently, once hitting a certain temperature down there (I was in Florida at the time where heat was an issue)..... it would expand enough, to open, and then boom, "black out"..... I replaced the Fusible Link, and that was the name of that tune..... I'm not sure of course about what happened to this gentleman's vehicle...... and I'm only guessing the same..... but the car did rain down upon the engine somewhat..... then I suppose there's the possibility of something getting shorted enough to cause a Fusible Link to fail.... that's what they're designed for..... blow apart upon a Big Shorts..... Also..... had a '64 Caddy, would do similar.... sometimes it would just lay there dead.... after playing with wires and cables and such..... finally discovered that the battery connection going to the block was just a bit loose and very dirty with some rust & corrosion..... so, Buffalo, NY.... winter..... salt, grime, loose connection.... = dead car..... cleaned the snot out of it, made it shine.... Done!..... Heat and especially Extreme Heat can separate, loosen, open up connections, melt wires, blow links, and fry other electronic components, especially solid state junk..... if it was my car, and it experienced torrential coolant downpours under the hood..... and my car wasn't starting or was completely Dead..... I'd totally visually check everything with great intensely, tighten, clean, polish all connections thoroughly, and take a Very Close look at those Fusible Links..... in any event, in the end, the integrity of my entire electrical system will have been greatly verified..... Food For Thought.....

indeed. as a matter of fact (and probably could make a pick quick out of this) had told about the last twenty problems 1.) hose of the battery to remove corrosion (we don't want to breathe any airborne acids) wirebrush the positive, the negative and the lolipop connection on the positive clamp. 2.) clean the connection to the chassis and to the engine dis-assembling the screw and cleaning the area of the chassis, the lug going to the engine should see nothing but metal capable of pulling 20 amps without breathin hard. 3.) reconnect with not too much force as to bend your clamp or bolt.