360 Pocketbook touch HD2 frozen on cover of the last book

Hello guys,

I have three years old pocketbook touch HD 2. Lately, I haven't been using it for around three months, and the battery probably drained out completely. I've tried to charge it via charger and USB cable for a whole day, but the screen is stuck on the cover of the last book. I've tried to hold the power button for 10 secs, tried to press and hold the reset button with a toothpick, but nothing seems to do anything. The power button flashes, it's lit up, a backlight of the screen glows, but the screen itself is frozen.

UPDATE: The battery doesn't seem to be a problem, when it's unplugged, the reader power button flashes. Also, I've tried to touch the display and make some gestos, and the gesto for the backlight and front light works! My display is bright as daylight and I can also try to add an orange backlight, looks like the control of the display works, just it won't change the display. Is there anything I could do?

Anyone have any suggestions on what could it be, or how could I fix it? Thanks. RMA is off the table, as I have it for three years.