More than likely, its a windows update has 'refreshed' some of your options according to its own sense of what you need to have. has done this to me personally. Your psu is an older design, group regulated (absolutely nothing wrong with it!) and those psus have a common problem with Intel C-states (the sleep modes) with any cpu Haswell or newer. The new cpus are far more economical and do not require much power in sleep modes, but the psu can't go that low, so there creates an issue. Win7 was easy to fix, but win10 has stopped much of the user control of power settings, including C-States.
So this means a trip into your Bios, what youll be looking for is a tab or page related to power settings, Some have S-1 or S-3 some have full ability to stop c-states below C-3 etc, and that's what you need, stop C-states below C-3. This still allow sleep, it just won't allow a sleep that's really deep.
Hope that helps