My deadbolt will not operate either manually or electrical without the key inserted

You likely have the lever that goes from the outside portion of the lock through the striker/bolt assembly into the inside portion rotated into an incorrect position when you insert it into the striker/bolt assembly.

With the door open, remove the interior trim (thumb turn) from the door, and using the key, turn the deadbolt to the locked position. Now re-install the thumb turn, in the locked position, and with the key removed see if you are able to unlock the deadbolt. I suspect that the tailpiece (part that sticks out of the lock cylinder and into the thumb turn) is not in the correct position.

I presume you figured it out by now, but if the tailpiece is installed wrong in many deadbolts, the key won't come out in one position or the other. It's called a "timing" problem and the way to fix it is to take it off the door, turn the tailpiece a half circle and put it back on the door. Usually Kwikset locks are designed so you can't put it in the wrong way, but it can happen. (If it's not the timing problem, then the deadbolt unit is defective or broken. They are designed to fail in a way that keeps them locked, so this could be a sign that someone tried to break in, or that someone used the extended bolt as a way to stop the door from closing and it hit the door frame too hard.)

The best way to install a deadbolt lock without the instructions handy is to look at the "lazy" cam and see if there is a way to install it wrong and don't install it that way. Example: If there are 2 ways for the tailpiece to fit in the deadbolt unit when the deadbolt is retracted and only one way for the tailpiece to fit in when the deadbolt is extended, then install the lock with the deadbolt extended and you can't install it wrong.

You would need to take it to a lock smith or an ace hardware. also bring one of the doorknobs so they can key it alike. Unfortunately, keying locks is not something that you can do without advanced equipment and experience.

it sounds as though the linkage that pulls the deadbolt back has disengaged... if you undo the screws from the inside of the door and remove the manual knob there will be 2 more screws holding the key lock to the door. A thin flat bar is attached to the key lock that goes through the deadbolt and into the manual knob. This bar turns with the key, sliding the bolt on its track to lock and unlock the door. Once the lock is apart check the key in the lock to see if the bar turns when the key does. then see if there is anything that may be obstructing the deadbolt from sliding. The locks are pretty indestructible so if there is a problem it may have been from the install... perhaps the door is to wide for the lock to engage properly and the lock worked loose in the 6 months that it worked.

It sounds like the exterior tumbler is bad, it is less expensive to just replace the whole deadbolt than to have the tumbler repaired.

Remove the deadbolt cover by removing the 2 screws. This will get you inside the deadbolt. Try using a screwdriver to pull it back. You may in the end have to break the unit in order to get it out and replace it. I have the same thing happen with a deadbolt. I ended up having to destroy the unit to get it out. You are going to replace it anyway so do whatever it takes to get it to unlock so you can then remove it from the door and install a new one. You do not want a deadbolt that will not unlock.

If it's like my deadbolt, pull the inside faceplate off. It's just pressed in place and the screws are behind it.

spray a little bit of oil where you insert the key turn it a couple of time to make sure it is lubricated then turn to correct location to pull out key hold cylinder in with finger key should pull out

Deadbolt mode must be activated and deactivated using the key in the driver's door. Insert the key and turn (I believe) all they way to the right to activate and all the way to the left to deactivate