My lenovo A2107A battery will not charge' - Lenovo 3000 N100 0768 - Pentium Dual Core T2060 1.6 GHz - 15.4in. TFT PC Desktop

you must be late some of the ways that you have on your tablet go in anything you do not want dail ate it and get rid of it that is the only way

Try a factory reset, if can. Else you should take it to service
https://www.youtube.com/watch?v=0uvU-bscH2g

Check your charger. If you don't have an electronic tester, you should ask for service. Also might diagnose battery issue

First, remove the (smaller) top part of the back cover. This is done by laying the device screen side down, putting your palms on the larger part of the back cover and using your fingers to push up the smaller part. It will not damage the camera- the camera cover is part of the back cover. The sd slot is on the left.

Should diagnose charger and battery. If you don't have the electronic tester, should seek professional assistance

Go to the control panel, and look for the Language or Location category. If there is a couple of letters in the bottom right of your screen, near the clock. Right click on it and change the language from there.

you have to install standard android developpement tools (SDK,ADT) ad eclipse (Juno latest release). Download SDK

Push and hold the on/off switch. OR, Pull the AC plug and allow the battery to drain. If it is under warranty, return it or replace.

Try here: http://download.lenovo.com/consumer/mobiles_pub/ideatab_a2107a_ug/data/EN/index.html OR HERE: http://support.lenovo.com/en_US/downloads/detail.page?DocID=UM015642

Had the same problem with a manufactured refurb, would go to 79 %, if you go to power options, change plan settings, change advance power settings, then to the Lenovo energy management tab, press the big enable Lenovo energy management, click on the blue gear to the left of the question mark, if "Optimize for Battery lifespan" is selected it will only charge the battery to 80%, change this to "Optimize for Battery Runtime" and it will charge to 100%