Ubuntu 20.04 is randomly shutting down within 1-5 minutes after I turn it on. It gives no warning messages. It is not a proper shutdown it just turns off. I turn it on again and again and it keeps shutting down in the same way.
The problem happens whenever I try to start Ubuntu. I thought it was a hardware problem, but when I dual boot Windows on the same computer it works fine. I can keep Windows on for more than a hour. It works fine until I shut it down.
EDIT -1
I look up on the previous boot's log. I literally understand nothing! Can anybody tell me what was the reason?
This is previous boot's log.
Oct 03 22:46:52 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-66 noise=-95 txrate=1000
Oct 03 22:47:08 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-75 noise=-95 txrate=108000
Oct 03 22:47:11 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-65 noise=-95 txrate=1000
Oct 03 22:47:22 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-75 noise=-95 txrate=108000
Oct 03 22:47:26 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-66 noise=-95 txrate=1000
Oct 03 22:48:09 Lenovo-G570 upowerd[1680]: energy 40.000000 bigger than full 0.000000
Oct 03 22:48:18 Lenovo-G570 systemd[1987]: Started Application launched by gnome-shell.
Oct 03 22:48:18 Lenovo-G570 systemd[1987]: Started snap.blender.blender.d1f998a5-d57d-45a1-8f77-c9c7148d783b.scope.
Oct 03 22:48:18 Lenovo-G570 systemd[1987]: gnome-launched-blender_blender.desktop-4769.scope: Succeeded.
Oct 03 22:50:09 Lenovo-G570 upowerd[1680]: energy 40.000000 bigger than full 0.000000
Oct 03 22:51:01 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-73 noise=-95 txrate=120000
Oct 03 22:51:06 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-64 noise=-95 txrate=108000
Oct 03 22:51:07 Lenovo-G570 gnome-shell[2162]: Window manager warning: Buggy client sent a _NET_ACTIVE_WINDOW message with a timestamp of 0 for 0x1200051
Oct 03 22:51:09 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-74 noise=-95 txrate=108000
Oct 03 22:51:15 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-65 noise=-95 txrate=81000
Oct 03 22:52:09 Lenovo-G570 upowerd[1680]: energy 40.000000 bigger than full 0.000000
Oct 03 22:52:28 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-72 noise=-95 txrate=1000
Oct 03 22:52:43 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-66 noise=-95 txrate=120000
Oct 03 22:53:51 Lenovo-G570 gnome-shell[2162]: libinput error: client bug: timer event5 debounce short: scheduled expiry is in the past (-5ms), your system is too slow
Oct 03 22:54:01 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-61 noise=-95 txrate=120000
Oct 03 22:54:09 Lenovo-G570 gnome-shell[2162]: libinput error: client bug: timer event5 debounce short: scheduled expiry is in the past (-3ms), your system is too slow
Oct 03 22:54:09 Lenovo-G570 upowerd[1680]: energy 40.000000 bigger than full 0.000000
Oct 03 22:54:48 Lenovo-G570 wpa_supplicant[1059]: wlp8s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-73 noise=-95 txrate=120000
This is previous boot's log.
