I think I'm closer to a solution; I've done a system restore (didn't help, but now it wants me to reburn a disk that I burned several weeks ago), updated all of the Dell drivers (still doesn't work) and in the device list there is an "unknown device" that I'm pretty sure is the bluetooth/WiFi card. In the knowledge base I found some techniques to restore that include going back to Factory BIOS, to clearing the NVRAM cache (that remembers what all devices are installed for a quick startup), or opening the cover and removing the coin battery for a few seconds then restoring it. Anything that involves opening the computer involves moving the desk, disturbing the newly-settled dust (I dusted last month), and wouldn't you know that when I start fussing about how peripherals are arranged something needs work. Or maybe something needed work so I started thinking about moving peripherals?

I'll try the turn off, unplug, discharge power, and remove and reinstall the unknown device showing up in the device list.