Do you have a Virgin Mobile Supreme Phone that is displaying an error message - "FTM" in a white box on the display? - Try this before a hard reset.

You may look on the web and read advice that you need to perform a hard reset and lose all the data on your phone - don't believe them.  Try this first: Remove the back cover of the phone, take out the battery for a few seconds, say 10, put back the battery, close the case and restart the phone. In my phone, it came up perfectly normal.