Power Management settings in F2 BIOS.  Select option to wake after power loss. When powering down, be sure to use Power Off in Windows.
Hi My previous Dell (XPS 8300) used to power on & boot by just flicking the mains power switch in the wall.My latest Dell (Optiplex 3050 MT) will perform a partial power on (switch on the unit will light up white & fans spin) but then turn off again, requiring me to press the on switch again, after which it boots successfully.Is there a way to change the settings so it will power on & boot from just turning on the mains switch?  
Can I power on & boot from the mains switch?