Have just completed upgrading my hardware; new x79 mobo, Xeon CPU and ECC ram, decided to try to boot the system up with my [previously A1 SSD running Windows 8.1 Pro] plugged it in, turned on and booted up...took a little longer than usual; but hey: it was 'configuring itself' I guess. Once password entered, went straight to the 'Activate Windows' screen...fair enough. Jumped through their hoops; but all well and good; system activated without having to re-install Operating System [figured a couple of hours frustration saved there...] but now I have noticed this issue, that was not an issue on the previous hardware; even if I right click the Start Orb, select 'Sleep' the PC doesn't...it just never goes to sleep. Have checked the settings in 'Power Options' no obvious problem there...anyone think of a cause for this problem? Would hate to have to re-install...but if I must; I will!