You would have to wait for it to run out of power. Then leave it off and charge it just a little. Once that was done, before doing the reset, try starting it up in "Safe Mode" and see if it will load. If it does load fine, some apps will not be accessible, but you should then be able to remove the file she installed and any other files that it installed. Once done, turn the tablet off and back on and see if it loads fine. If it does, you are good. If it doesn't then the file may have put a virus, malware or other things on the tablet that will need to be removed.
To get into "Safe Mode" please do the following.
1. First turn off the tablet.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then...