Mic problems

[cd213]

My friend is having a problem with recording on his computer. This is his problem as he told it to me:

 

Any type of audio I record into the computer, no matter if it is extrenal from a mic or internal (stereo mix) does not record clear anymore. Usually it would record in the same audio quality as what is coming out through the computer, but now when it records the levels are not consistent and it sounds very hissy and muffled during playback.

 

Any help would be great!