What do the system logs say? "sudo journalctl -b-1" after a reboot and jump to the end.
this post was submitted on 11 Feb 2026
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honestly, you should give less info. what's your hardware? what PSU? drivers? X11, wayland? what's that "running again" business, what was the issue before?
How new are you to Linux?* /gen
Have you checked the output of, say, “journalctl -b -2”? This would give you a system log of messages that go back to two boot sessions ago and normally show you what happened just before that first shutdown.
This could be drivers, background processes, hardware, no way to know without starting by looking at logs. Hell, I’ve had a monitor crash out my system multiple times and I wouldn’t have ever guessed if I didn’t check my logs and dmesg output.
* to get a better sense of how to help you
FYI you can add -r to show the log in reverse order.
I bet you it's a hardware issue.
Run Memtest+ to check the RAM first...
Might be a PSU / heat issue....
Make sure the fan is not full of dust. Clean it out if it is. Most systems shutdown/reboot if it gets overheated.
Make sure your RAM and all other connections are properly seated. I’ve had reboots in the past because a stick of memory wasn’t fully seated, even though the clasps were locked in place.
Is there anything in the journal? If you're not familiar, try something like journalctl -o short-precise -k -b -1 and then look for anything weird.
Up and running again suggests it wasn't running before. Why not and what did you do?