Replaced glass screen (digitizer ) a week ago - which included disconnecting and reconnecting the CMOS battery.  Now the machine will not boot up.  I only get the DELL splash screen with the 5 white dots rotating in a circle - and then some Advanced Options prompts.  I have tried all options and they do not work.  I end up in the same place.  What do I have to do to get the machine running again?  Thank you for any assistance anyone can offer.