Car wont start,shows no sign of power

Get a wiring diagram and check for other major blown fuses. https://ricksfreeautorepairadvice.com/car-wont-start-but-has-power/

The light you see is a security light. Usually it shows up when the security system is armed. If the light stays on then I would suggest getting in the car and closing all of the doors. Then press the lock button on the key fob. Then unlock the car with the key fob and it should go away. Try starting the car afterwards to see if the light goes away if it doesn't when you unlock the car with the key fob.

Usually a sign of something draining the battery.
The machine test probably showed the battery could hold a charge and the alternator was charging the battery.
You may need to have someone check for a power drain.
When the key switch is off, there may be a weak short to ground or a relay or component that is using power.

To begin with, the "suggested" answers you might see at the bottom of the screen are not always answers for your question or car.
When you turn the key on, you should be seeing all of the warning lights as a bulb check.
If not, the gauges fuse could be out, or a wiring problem, or an issue with the key switch. The check engine light is powered thru the computer so the computer fuse could be out.
Based on what you have said, I would check the key switch first.
You may need to get a book to have all of the wiring diagrams.

Body Function Control ( or computer) usually a 5 volt source that sends signals to individual places, Like gauges, have you replaced the radio recently? the BCM could have gone bad which regualtes what the BFC does,

I would have the battery checked out still, it don't take much power for the radio to work, and by what you say, that the gas and temp. gauge jump up and down when trying to start, that tells me weak battery,most auto parts will do a free battery test for you,have it checked out. hope this was very helpful.

No, but if you put fuel and the gauge shows empty, then you have a loose connector near the gas tank. If car doesnt start, then it is for sure that the connector of the fuel pump is loose. Reconnect the fuel pump and you are gonna be fine.

try proper jump cables and not the cheapo chinese ones ,put battery on charge for about 3 days with a trickle charger to de sulphate the plate and try again

you have a problem with posibly witht he adjustment on you neutral switch. the transmission has this to prevent starting in gear. it obviosly works fine in newtral so it needs to be adjusted or the lever on your transmission needs adjust ment to allow this sensor to do its job
i hope this helps

bad altenater