Random PC speaker beeping in Windows 98

[Zuofu]

This is a weird problem and I'm not sure where this goes...but I'm getting some random PC speaker beeping in Windows 98. Its a very short single beep that occurs every 20 minutes or so (usually in IE). I checked my temperatures and they were not high enough to trigger the temperature warning (about 30-35C). No strange applications running in the background either...anyone have any ideas?