Why does my tablet when i turn it on it has a battery sign with an explanation mark inside it and will not turn on

That exclamation mark means the battery is bad or has a bad connection inside the device. If your battery is user-serviceable you could try removing the back of the device and checking the connection for corrosion or looseness. Depending on how old your device is, it just might be time for a new battery.

meaning the battery is deffective....it cannot be charged..i suggest use a power bank...if you do not want to open your tablet and replace the battery...use powerbank instead. it is quite bulky and heavy, but it is worth using...when buying powerbanks, look for the highest mAh rating..Mah means miliampere hour...or the discharge value...the higher the value, the longer the time the battery is discharged

battery low or not enough battery left or need a new one!!

Can the tablet turn when plug in to ac adapter/ home wall charger?
Maybe I can help you if you can tell me the model of your tablet.
EZBUY batteries and chargers laptop batteries

Without further explanation, pictures or details of what you tried, it's hard to tell what exactly is wrong with your Nook. However, assuming that the battery is still good you will need to "reboot" your Nook.

Unlike other tablets, there is no reset button, but you can try this.

While pressing the Nook button (upside down u on the front of the tablet), press the power button on the side. You will need to hold it for couple of seconds.

That would be the charger or the usb port that charger goes into. the red ! battery is saying the battery is dead

it probably means it has low battery or that there's a problem charging it such as something might be messed up inside the tablet causing it to not charge.

I had this same thing. The Batter image had a red line on the right side and the yellow triangle had an explanation point in the middle.

I searched the net and found a few solutions.

1. Hold the power button down for 30 seconds.

2. Hold the power button down and the volume down button at the same time for 30 seconds.

3. Just let it charge and over night and it should go back to normal.

I did all 3, in the order I wrote them. While in step 3, after about 5 minutes I pressed the power button and it showed that it was charging normal.

Hope this helps.

My Pandigital screen is frozen, all I get is a green android with a triangle with an explanation mark inside it. How do I reset this?

Remove battery and reboot the device.