If you are running the Avatar ROM that means you have a custom recovery on the tablet. I would download a new ROM, put it on your sd card, factory reset, wipe cache, wipe Dalvik, and flash the new ROM.
If that doesn't fix your issue then it very well may be hardware related. For some reason i'm thinking something has become corrupt somewhere and that's causing your problem. You'll know after you've flashed a new ROM. If the problem still persists then it is probably hardware related.