Do you have a disc that came with it? If so, there should be something on there titled "MP Utilities 3.68" or something similar. The program MP3 Disk Tool is the one that will help you format your player. Follow the instructions posted here:
How To Remove a Memory Hack.
Also, where did you get the player? If eBay, what seller? If you could put a link to it or a picture it might help us identify the player and come up with some solutions.