Ok so i have a SPI mp3 player and when i sync a song.......it won't work. There's always an error on WMP!

If the error message is saying your MP3 player is full (but it's really not) then I don't know what to tell you other than to format the player. You can do that on the site below. I used to have an SPI player and there were a lot of problems with it. I'm good with MP3 players but this one still gave me a lot of trouble. It's also very hard to navigate. Anyway I returned mine and got a much better one. I guess you get what you pay for..