I use Firefox almost exclusively as well. (I've used Chrome, IE8, Safari, and a few others).  No problems with RCU. But the discussion wandered towards security packages. Comcast provides (as a surrogate vendor) a security suite. Used to be McAfee. All was fine. Recently they switched to Norton. Seems that Norton installs an add-on that includes a couple of menu bar items. It "appears" that when ever this add-on is "tweaked" (non-technical term for heck-if-I-know-what-I-just-did) my machine looses internet connectivity. My other machine with XP (this one has 7) and Firefox keeps on "truckin'" but to get the 7 machine back I need to manually reset the old router (Linksys). I've swapped all the hardware to fresh stuff to no avail. After a couple of boot cycles things magically disappear. All the time the XP machine is just luvin' life.

IE8 doesn't appear to "hang" the internet connection through ... Comcast tech support points to Norton. Norton points to Comcast saying that it's an internet connectivity issue. I LOL when the tech said that! I was using a VOIP telephone that requires a viable internet connection - and I'm talking with him (India). He refused to entertain any discussion until the internet connection was re-established and hung up. Things that make your day ... [:@]