Keystrokes stick in Yahoo Mail ONLY.....argggghhhhh?

Does anyone know what the problem is when trying to type an email, either to send or respond, it seems that not all the keys work. You have to hit a key 2-3 times just to type a complete word!! I thought it resolved itself last week but now it is happening every single time I try to email!!! It ONLY happens in Yahoo Email.....someone please help =(