I run the Pandora desktop gadget on my Win7 machine at work. I listen w/headphones, but since the headphone jack is on the front of the machine, sometimes my foot catches the cord and pulls it out. When this happens (or any time the headphones are pulled out), Pandora stops playing and has to restart/reconnect. Is there some reason why this happens, and how can I prevent it (short of being less clumsy)?
This may or may not help, but I've noticed that (hardware permitting I assume) Windows 7 recognizes the fact that audio devices are being (dis)connected, and will occasionally pop up an alert when you plug in a new microphone, for instance.
Have you tried going into the 'sound' control panel item, looking at your 'speakers' properties in the 'playback' tab, tabbed over to 'advanced', and trying different checkboxes in the 'exclusive mode' section? That's what I'd try first if I were running into that problem.