Why does yahoo hate my built in mic?

Every time I use video call it says there is no mic. Every time I use voice call it disconnects me immediately. I have done all the configurations and it all works on there but it still won't work in the chat. I have been sending the error reports and I get nothing in return. I have the equipment and I want to use it! But yahoo refuses to let me. It is getting tiring to have to fight with it all the time. Does anyone have any advice that could help me to solve this? I appreciate any help. Thxs!