m250 does not work

This is exactly what is happening with my daughter’s m240.  We gave it to her for Christmas. She was listening to it today- turned it off for 30 minutes - tried to turn it back on and it won’t get past the SANSA screen.  The computer will not detect it no matter what I do.  I’m glad that I found this forum as the SANSA website was not much help.  The info has saved me a lot of time!