It had stopped doing this but now it's back. I've tried disconnecting all of the USB devices I can and changing Windows power settings, but nothing seems to have helped. It used to reboot instantly (like the below video) but now it can take several minutes. I have to login and restart all my programs. What happens is I go to Start > Sleep and the PC goes to sleep as you'd expect, but a few minutes later it powers up again but this is a full boot from scratch (you can see the lights go white instead of blue and the MSI BIOS boot logo appears) rather than waking from sleep. It had resolved itself a few weeks back but for the last week or so it's come back. I have a weird problem with my PC that started a few months ago.