Entering Safe Mode will help you to troubleshoot any app in your Android tablet that has been affected by a virus. Much like Windows OS, Android also has the Safe Mode option, which can be used to fix any glitches in Android devices. To reboot your Android refurbished tablet in Safe Mode, tap and hold the Power button for a few seconds, and then choose Reboot once the prompt appears on the screen.
If you are on Android Nougat, tap and hold the Reboot prompt until you get a prompt to Reboot to Safe Mode. Tap on the prompt, and then tap on OK to confirm and enter Android tablet in Safe Mode. Alternatively, you can also tap and hold the Power button and the Volume keys to reboot the device in Safe Mode.
Once the device reboots, you could see the watermark Safe Mode in a corner of the screen and the background will be black as well. Navigate to Settings > Apps > Downloaded and then go through the list of applications which you have downloaded on the Android tablet. Tap on the app if you can find it and, in the next screen, tap on Uninstall.
The downloaded app may be hard to find in Safe Mode, so think back to when the virus problem started and try to remember when you downloaded the app. Then scroll down the downloaded list, find the dates mentioned next to the app, and tap on the Uninstall option next to it.
However, if you cannot uninstall the malfunctioning app, then chances are the app may have the Device Administrator Access. Navigate to Settings > Security > Device Administrators in Safe Mode. Then find the app, tap on the checkmark next to the app, and tap on Deactivate when Android prompts you to do so.
Now, go to Settings > Apps > Downloaded to retry and Uninstall the app. Once you uninstall the virus-detected app, reboot the Android tablet to exit Safe Mode and use the device normally.