Remember, you have a 1-year warranty–you may want to use it (telephone SanDisk customer support). It could be a chip issue.
You also could try, if not recently done: a system re-set–Clip off, hold the on switch uppermost for 15-20 seconds; a reapplication of the firmware (it could have become corrupted over time)–see the sticky thread on firmware upgrade at the top of the forum; and/or a reformat, from the Clip’s settings (note: this will erase your content on the Clip).
