Why is it continually indicating battery is overheating?

Could be the battery has gone bad.

Are you actually turning the tablet off when you are not using it? (Hold down power button until Power Off box appears on screen)? If not, your tablet is constantly using power even with the screen blanked and will drain the battery. You could have a bad battery that is no longer holding its charge. How long can you run the device off the charger continuously? That length of time might indicate the state of the battery. Check the manual for expected battery life, which for a Linx 7 is usually 4 hours or less.

remove the memory card , an reset it . small pin hole in side.
use a free program manager to see what is running at all times . uninstall or disable them programs in your startup.
go to your settings an disable all updates .
it might have a memory or cpu issue too.

Upon first use, you have to charge the battery overnight. Then for every recharge, you may have to keep it connected to the charger for at least 4 to 6 hours depending on your tablet, otherwise, your battery will go kaputt in a short period of time.

To help you, it would help if you posted model number, also, if there is a carrier you could list as well.

It could be a number of things. Too many programs running. Or prolonged use while on charge could cause overheating.

replace the battery for starters
check that the charger is putting out the correct voltage

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The laptop may be overheating.
When the CPU overheats then it will shutdown (i.e. thermal overload) and won't boot up again until it has cooled down.If this is the problem is not fixed then the CPU will eventually fail.
A faulty fan causes this problem or the fan and heat sink assembly are cloggedwith dust.
Check the CPU fan to see if it spins freely, if not replace the fan. If the fan and heat sink is clogged withdust the remove the dust and make sure the vents are clear and dust free. Use acan of compressed air to do this.