My Lights, Radio everything come on no problem but my mitsubishi endeavor will not start.

You need a new battery.

Try to reprogram key by turn key on and off 3 to 4 times and try again

Depending on the make you can go online, search the make/model/serial number on specialist website that will sell you the code for a couple of bucks. As you didn't provide this in your question I couldn't test run it for you. Serial number may be in the drivers book or remove radio and it will be on the back. Has nobody written it in the owners books anywhere? Next time hook up a small motorcycle battery to your main batt leads before you remove the main batt and this will keep the codes in place while you swap the main batt.

Here is how to remove and replace brake lights

This is caused in may cases by a defective antenna ground to the chassis of the car or a defective antenna lead to the radio..

I had the same problem too..My battery was stone dead..My lights were on but their probably isnt enough cranking amps to start the truck...I would take the battery out and charge it overnight and then try to crank it in the morning...i just changed the battery and the truck started right up

I would start with the battery. Probably weak or poor conections Need to clean.. TRhen check your connection at the starter... Make sure you have a full charge

Do you have anything aftermarket in the vehicle?

Sounds like a possible BCM body controll module has shorted out partially. I think these are only at dealerships.

Dodgy fuses/ wiring