Help!!!!please???

ok i all the sudden when some one ims me on aim the box pops up and you can see every thing, and you can hear the im send sound, but the ims that get sent from both of us are invisible. i can even see what i type in the type part but when i press send it makes the sound but nothing shows up in the box. i know its not colors and i know its not the other person cause they can see the ims on their computer