I have exactly the same problem, although it's more like every 30-40 seconds for me.
preveously, I had build 7000 installed on this machine and it was having no problems
I suspect that some device did not install it's drivers
properly and is being removed and added every few seconds. Is there a good way to tell the source of the refresh? or to figure out what devices are installing and uninsalling themselves?
I thought about using process monitor, but I am not familier enough with the program to effectively use it.
Any help would be apprecated, this constant dinging is driving me batty (and i know that i could turn of the sound, but that doesn't solve the root problem)