This story clearly illustrates how important it is to check the simple things.
I've been plagued by cable modem disconnects for all of the time I have been on broadband.
Finally, last night, after three service calls to my house in the last month when the disconnects were happening upwards of 5 times a day, I finally took the router out and connected directly to the NIC.
Lo and behold, the Cat 5 cable I was using for the WAN connection to the router caused a loud hum over my studio monitor speakers when I connected the Cable Modem directly to the NIC.
I immediately concluded that the generic Cat 5 cable (which my nephew provided when he made a gift to me of my Linksys router)was faulty and immediately instructed my wife to do the right thing and lift 3 replacement Cat 5's from her office *g*