tablet will only turn on if plugged into the wall

I wondered if that was the problem when the battery died. A multimeter showed everything from the wall to the battery itself to be in working order (assuming this battery can be tested in the same manor as other batteries. ie: AA batteries) it become so dead it would no longer recognize any charger. I seen where some ppl had luck unplugging and replugging it. This did make it recognize the charger again and showed that it was at 1%. After a few minutes the screen was full of flickering lines where the image had previously been. A battery boost go it to 15% & powered on without being plugged in. Transferred all my files just in case it died again. shut the tablet down & put back on charger. Battery got up to 85% but then slowly started to deplete again. I considered ordering a new battery but I have no idea how to remove the old 1. Its glued in very well & whenever I attempt to remove it the battery bends which makes me kinda nervous. Is there a safe way to remove the old battery without harming the tablet?

I wondered if that was the problem when the battery died. A multimeter showed everything from the wall to the battery itself to be in working order (assuming this battery can be tested in the same manor as other batteries. ie: AA batteries) it become so dead it would no longer recognize any charger. I seen where some ppl had luck unplugging and replugging it. This did make it recognize the charger again and showed that it was at 1%. After a few minutes the screen was full of flickering lines where the image had previously been. A battery boost go it to 15% & powered on without being plugged in. Transferred all my files just in case it died again. shut the tablet down & put back on charger. Battery got up to 85% but then slowly started to deplete again. I considered ordering a new battery but I have no idea how to remove the old 1. Its glued in very well & whenever I attempt to remove it the battery bends a lot which makes me kinda nervous.