Sandisk is always up upon disconnect. Can not get to music or screen selection

I would appreciate anyone who could give me a hand. I have been trying to figure this out for a while now. Every time I connect my Clip to USB I can upload songs. Once I disconnect it locks up. Any suggestions other than hold power for 15 seconds?
Thanks

Can you elaborate on this.  I need more details than this to help you out.  What do you mean it locked up?  Does hard reset work?  Anything else? steps of doing it and such.  Here is one thing to try out.

  1. Force device to MSC mode (slide the power button backward into HOLD mode and press-n-hold the center button while plugging in PC)
  2. Once it’s connected under MSC mode, please do a FAT16 format
  3. Unhold and unplug from PC and see if it will work again