Notebook Boot and Lockup

Hope this is the right place to post this, but randomly my laptop started just shutting off and restarting. I’ve done extensive diagnostic tests and all passed, I even switched off “restart when an error occurs” but it restarts anyway. I’ve scanned with two different antivirus programs, both which have given me the all clear (I uninstalled one to test the other). I’m at a loss. I got this refurbished so it’s not unlikely it’s not perfect, but even so I can’t find any reason it’s doing this, all memory is the same make and type so it wouldn’t be anything to do with that.

Currently all hardware is at about 34c idle with a couple of programs open. It doesn’t seem to be too hot. It’s warmer where the battery sits and when I plug it in it’s a little hot but that’s normal I assume. Randomly however the CPU will shoot up to 65 at idle and then just cool down again to 30.
I bought it in December 2017, so about a month ago. I keep it on a flat clean surface so I highly doubt it’s dusty either.
CPU usage is is 8-11% and memory is 42%.


That’s about all the info I have. It doesn’t seem unresponsive at all, the new windows update made performance a little rough (and I had massive problems trying to install it), but otherwise it’s pretty responsive and runs perfectly fine.

I use Speccy to read my system info and used the HP diagnostics tool in startup to test hardware. If you have any more suggestions for diagnostics tools I’ll be happy to download and try them too.