Recently my Inspiron 5100 with XP has failed to boot completely when powered on.  I get the initlal Dell screen, the fan goes on, but nothing else happens.  I hold the power switch down several seconds to turn off the machine, then press it again.  This time, the computer starts up normally.  Dell support sent me a long email with several suggestions (which suggests to me that they don't know what's happening here).  Has this happened to anyone on the forum?