Mystery Audio

Hi Folks, my sister has windows 98 with aol installed. When she logs on to aol after a few minutes but not all the time, an audio stream blurts out her name. There are no IM’s that she is receiving and she has no clue how or who is doing this? The only thing I can think of is she opened up an email with an attachment that had a program that installed itself on her hard drive, sought of a gag virus, not to do harm but to annoy. Any ideas ?