Just a build on my last post
THIS IS THE ONLY THING THAT WORKED !!!!
I hadn't used my tablet in a couple of months and it wouldn't turn on no matter what combination of buttons. So, I tried pressing the home button while plugging in the tablet and pressing and holding the volume up and power buttons. The tablet powered up after about 30 seconds and I selected the option to restart the phone. All good now.!
Just a build: Even though I had plugged in the tablet to charge it overnight, it would not start. When I followed the process above and the tablet powered on, it the battery was dead so something prevented the tablet from charging when it's battery was 100% dead (hadn't powered on in a couple of months). Now the battery is charging and the tablet seems to be working great !