Music to Phone

ok so i got my LG black chocolate about a year ago this coming christmas. I put music on it of course when i bouight it and had no problems with the cord and the disk, butt......now i tried to put new music on and for some reason my computer wnt recegnize my phone yes its the same compute i used a year so it sholud have the data already on it but it doesnt I installed the disk and im sure the cord works but when I plug it in andopen sync music Windows Media Player wont recegnize it and it wont come up its sez that there was some kind of an error please help I wolud really like some new music and for what i payed for the phone when it came out i kinda wanna use it

thanks SD