The drivers all disappeared again - USB, sound, wifi, ethernet... luckily, not video or input. This time, I was able to system-restore to save the Windows 7 (Pro, 32bit) installation. Restoring to before a Windows patch (2 days ago) didn't do anything. However, restoring to before I installed the above software did fix the drivers. So I'm worried the AVR-related software is at fault. There's a chance the problem lies with a wireless mouse I started using today, so I'll avoid it and see if the issues reappear.
Et Cetera Res 