After different windows updates now have two totally different PCs displaying same problem starting up. Talked to other users and it’s common problem. Windows either goes to black screen at some stage during boot up or gets in ok and quickly loses mouse and any input control. Only option is to switch off. Usually ok when switch on again, but have had nerve-racking moments. We have evo ssds installed but friends have not. Have now turned off fast boot option in power settings and possibly better but not fail safe.