Hi,
If your tab is no longer covered by warranty, you may wish to try the following, and if Acer says it's dead you have got nothing to lose.
'''NOTHING SAYS THAT THIS WILL WORK!!'''
This involves opening the tablet to disconnect the battery connector from the battery (you don't have to pull out the battery just disconnect it), then press the power button for about 30 seconds then reconnect the battery and see if it has reset enough for you to perform a factory reset.
Here is a IFIXIT link for an 810 model hopefully it is close enough to guide you. ''(The battery connection appears to be different between the two models)'' [guide|37623]
Here is a link to a not very good guide to disassemble the 830 model
https://mikecanex.wordpress.com/2014/04/23/acer-iconia-a1-830-disassembled/