Bleeping sound similar to pluging in devices on windows

[orangedavie]

Does anyone have any idea what could be causing this. Its pretty random can be 2 or 3 times in 5 minutes or can be evey half hour. Just got a MBP 13" installed snow leopard. In the background I have messenger for mac and entourage running it does not seem to coincide with new messsages or emails. Im using Firefox as browser, which is regularly freezing. Hope the info helps.

Thanks for anticipated help.

 

[omgitscro]

Facebook chat?

 

[orangedavie]

All that is running in the background is mac for messenger and entourage. I dont use facebook chat.