Desktop reboots itself on sleep or hibernate

The problem is that your mouse or your keyboard automatically wakes up your computer when you want to put it in sleep. To disable this behaviour go to Device Manager, choose your mouse / keyboard and disable something like "This device can wake the computer up." This worked for me. :)

For me, it usually ends up being network devices and WOL, even when that feature is disabled in the BIOS.

In your device manager, make sure you uncheck "This device can wake the computer up" as KovBal said, for your network cards.