Every time i startup my XPS 12 9Q33, the dell logo appears and the circling dot pattern begins below, before the system freezes. If i then hold the physical power switch in the 'engaged' position for between 4 to 10 seconds the system shuts down. Weirdly then on the next attempted startup i don't have any problem and the system functions normally. Any suggestions? I ran f12 - diagnostics. No known problems