I had 3 to 4 times in the past days. The other problem I'm facing is unusual draining of battery power. It goes like that, my x51v battery power was 70+ % and I switched it off using the power button. Before I power off, I've checked that no program is running, WiFi and BT was not turn on. After 15 hrs later, it was drained to 4~11 %. I had to do a soft reset to power it up to check what was the battery level. Anyone encounter this?