Audio connection problems

Question

Up until a week to 2 weeks ago I could converse in Yahoo Messenger & Yahoo/Yazak Chat; could hear & be heard..Now it is not so. I tried running Yahoo Audio Setup Wizard; but it gave 5 reasons THAT was not working, and none of those reasons apply...#1) other audio applications are open.Close all other applications & retry the test..although I knew this was not true, I completely shut computer down to start all over again.
#2 You have no sound card installed...if I have conversed on this internet for 4 years that disproves that. #3) the sound device/drivers may be corrupted & #4) the sound device does not support any suitable wave format....this also proven untrue by almost 5 years of use..and right at this time I can HEAR music and singing with SingSnap...if there was anything wrong with my sound device I would not be able to hear that.