ipod shuffle recognition and recharge

My ipod shuffle flashes green then green and orange very quickly when I plug it into my computer. Neither the computer nor itunes recognize the ipod, so I cannot get it to charge or download, etc. The charge is very low, but it still plays just fine. I downloaded itunes 7, but it doesn't seem to have changed anything. I've tried resetting it, but that makes no difference. I've also gone into programs and tried to gain access through updates, etc. Any thoughts as to how to get my computer to recognize the ipod so it will recharge and show up in itunes?