Why won't my tablet turn on?

I initially was having a problem with my tablet taking a long time to charge. So, i found a YouTube video that suggested disconnecting and then reconnecting the battery wires. I opened it up and did this but it didn't seem to help. Then a day or two later when I took it off the charger, it would not respond. So I put it back on the charger and then it would work. I even had 100 percent battery capacity. However, after about an hour of using the tablet, it blacked out and has been unreponsive every since. How can I fix this?