Try FORMATTING your player in Windows to see if that helps as well.
Players restarting can be an indication that you have a HACKED player. This is where the seller or manufacturer has hacked the player to show more memory than that is physically installed on the player. So as a consequence, the player restarts when it tries to access that porportion of the hacked memory.
Try formatting first, if that doesn't work, then try following the guide in this post here:
How To: Removing Memory Hack
Also try using this tool to see if it can tell you how much memory you have -->
Tool: H2testw - To test hacked flash memory.
Hope that helps.
Let me know how you get on.