Please update the firmware.
Use following link to download firmware to your PC:
https://svc.prestigio.com/Service_Files/eBook/PER3664BC/PER3664B_20140513_V1.6.zip
1) After downloading to your computer firmware Folder, extract (decompress) the file from the archive (the folder).
2) Use user manual for upgrading which inserted inside the archive.
3) All data on your device will be erased after installing the Firmware.