Sansa Clip + frequently locks up

My Clip + frequently locks up while playing.  It will get to a song and just not play it, so I have to crash out and start playback again.  Do I have a bad player or is it something with my mp3 files?

Do you see a pattern in which songs it locks up on? Is it just a few songs?  What format are the problem songs? Did you run chkdsk on these songs to make sure they are not corrupted? If it is just a few problem songs, did you try deleting them from the player? Do these songs play fine on your pc? I’m confused. Is it locking up, or skipping some songs or both? Are any of these songs protected? If so, how were they transfered to the player?

I don’t see a pattern to the songs it locks up on - all are mp3’s. Seems like it is about 10% of songs and these songs play fine through Media player on pc. It is locking up at the very beginning before song even starts and these are not protected files.  I transferred using Media Player. I’ll try deleting the problem songs, but it seems like I will be deleting a lot and then I guess try adding them again?