Laptop screen turns completely off when idle, forces me to restart.

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Hi, this is a bit of a random thought... and granted you say 'the laptop is still on'. Nonetheless, try disabling hibernate (= delete hyberfil.sys).
Enable or Disable Hibernate in Windows 10 Windows 10 Performance Maintenance Tutorials
That should at least eliminate the chance it's hibernating- or attempting to.
(Noted your specs say desktop, but you're referring to a laptop)


You can try (from an admin command prompt)
powercfg /SYSTEMSLEEPDIAGNOSTICS
to see if anything you see is related to sleep.

Interestingly my external mouse and keyboard turn completely off

- seems to indicate it's nothing to do with the screensaver.

What sort of PC is it? Could you add to your specs?
Are you using a USB wired or wireless mouse and keyboard?
When it's non-responsive, does the touchpad do anything?

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See
Monitor turns off after 2 minutes of inactivity - Page 3 - Windows 10 Forums
#22

There are many many threads posted on unexpected sleep events, but this hasn't occurred for quite a long time.
E.g.
Windows 10 sleeps after 3 minutes, no matter what. Solved - Windows 10 Forums

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Plokoon,

When a problem such as this is triggered by a display event [such as the screensaver kicking in], it is possible that the problem is caused by the display driver being corrupted or not compatible with the latest Windows update. Try going to the computer / display card maker's website and installing the latest version [just using Device manage to check for an updated driver would not have the same effect because it has no means of knowing if the installed driver is corrupt or not].

Denis

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