Yoga Tab 3 help

[IAR117]

Hi. My sister bought a Yoga Tab 3 a few months back and it was working brilliantly up to recently. One morning she turned it on to find that it was going to the lock screen and then the screen turned black and then to the lock screen again. It was stuck in a loop and when I say screen turned black, I could tell the display was still on and that it wasn't off. I had a look at it and tried rebooting it by powering off and on again as well as hitting the reboot button. I had an old phone that ran android 4.2. When it went bad I held down the power button and volume buttons for about 5 seconds and I could do a hard reboot. Would you guys recommend doing the same on this? Bearing in mind it's still within the warranty period. Any ideas on how to fix this and prevent it from happening in future? TIA

[Archemedus939]

A hard reboot or reset would not void your warranty, I recommend you get into recovery mode, and wipe date/factory reset and your device would be back to normal. Only downside to this is that all the data on the device would be lost in this process. Only flashing a custom rom or recovery would void your warranty, so there is no harm in trying to reset the device.

[IAR117]

Is there a way to back up the files on the tab onto the cloud from a PC before the factory reset? Also, over the weekend I went to the shop where she bought it and they reckon that it could've been a virus. No signs of the new ransomware virus, so that's good news.