a) Try a factory data reset and check if this resolves the problem.
Be aware that a factory data reset will erase all your data and downloaded apps. It will restore the tablet to its’ default factory condition (or last system updated condition)
Therefore it is important to backup the tablet before performing a factory data reset if you do not wish to lose all your data and downloaded apps.
Also ensure that the battery is fully charged before performing the reset.
Backup the tablet using the tablet’s backup my data feature.
Once the backup has been completed, reset the tablet using the tablet’s factory data reset feature.
Once the tablet has been reset, check that the tablet operates correctly.
If it still doesn’t operate correctly see option b) below
If it now operates correctly then using the backup you made earlier, restore the tablet using the tablet’s automatic restore feature.
Once the tablet has been restored, check that it is still operating correctly.
If it is then the reset has resolved the problem.
b) There is a 90 day/1 year limited manufacturer’s warranty on the tablet. You could make a claim for a manufacturer’s warranty repair or replacement."
"Your battery may be damaged or no longer holding a charge. You will need to replace the battery in either case. Link: Ematic FunTab 2 Battery Replacement
The motherboard may also be in need of replacing due to some damaged connections or other various reasons. Here is a link to replacing the motherboard Ematic FunTab 2 Motherboard Replacement"