Whn I send an IM on Yahoo Messenger my friend can receive it but I cnt c wat I sent or wat my friend replied?

I send Ims but I cannot see what I ssent or what my friend replied. But my friend can see what i sai. I see (their name) is typing, and last message sent at ????????????. I have tried yahoo help, change font color, sigini out and back in, installing, and reinstallin yahoo messanger. please help!!!!!!!!!