Had same problem. If you do a reset, you will clear all the songs off your Sansa and any settings - will be like it came from the factory but without their sample songs too. Totally blank. Hope you backed up your songs to CD or harddrive or other.
To do a reset, put power button up (like turning on or off) and hold it up for about 15 seconds. The screen will refresh and your device will be reset.
TGG
October 2008