hi i can;t use my chat?

[Darlene]

when i try to put available or busy it won't let me do it. if it say's disconect i try to get it to say available and it will jump right back to disconnect. then it will say that your chat has ended because of you being signed on to yahoo messenger on this computer or some other computer and i''m not signed on to another computer. please help me fix this problem . i can't chat with any family or friend's because of this problem