Screen on the K88 Tablet goes to sleep or to black in 5 seconds

Go to security settings and choose automatically lock and select immediately

Hmmm, under Security there is no such option as select immediately after sleep  in that entire section.

Are you sure you are talking about a ZTE K88 Tablet from AT&T, and not some other device?

Yep, you were right it was  worth  a try, but unfortunately  it  doesn't work.  

Go to security and tap on the screen lock setting icon to the far right, you'll see it there in the drop-down list.

Ahhh, no such option in that drop down.

They moved it under a GEAR icon on the security but that Gear does not show up unless you have some form of screen lock selected (other than None or  Long press).

Found it now. 

Set it to lock immediately after sleep.

Set Power button to lock immediately.

Set Display to sleep in 2 Minutes.

Exited settings.  

Counted one-one-thousand ... ...

Tablet switched off, and locked in 6 seconds flat.

Rebooted, just to see if that fixed

Nope.

Set it to Lock two minutes after inactivity (also still used for display sleep setting)

Test again.  NO Joy.

Thanks for helping.... But:

Looks like I'm going to have to factory reset this device.  

The  AT&T guys that posted on this chain were useless, big surprise there! What a pain!

@davidcrosby   thanks for trying to help !