Yesterday, my four-month old IdeaPad Flex 5 underwent a LENOVEO update. Since then it will not stay active. When I boot the system I am able to use it for anywhere between a few seconds and a few minutes but then the system freezes. It does not unfreeze on its own. I need to hold the on/off button in for 20 seconds and let the machine shut down. Then I reboot and the system comes up perfectly. Then it freezes. Then I reboot. Then it freezes. Any suggestions?