I had a similar problem: My sansa would insist on refreshing the media every time I turned it on. I found some info saying that there is a glitch in the flash card slot. I removed my sd card (never used it much anyway) and haven’t had the problem since. Since you don’t seem to have an sd card in it… and assuming you still have your sansa (this is an old question, it seems), if you hold the power button and the volume-up button for 20 seconds, you can force a reset. (Caution: holding the power and volume-''down'' will give your sansa a factory-reset, wiping all of your music. Useful as a last resort.)
Hope this helps a little…