Testing Sansa Clip Memory

How do I test the memory on my Sansa Clip 1G memory.  Every now and then when listening to a long MP3,

usually a CD of a book I have converted to MP3 format, I hear a loud rasping pop sound an a track repeats.

I suspect a possibile memory problem.  When I bring the set of files up on my computer,  I see that the track

has been replicated.  It wasn’t this way before listening to the tracks.