The pop-up (see below) just appeared between yesterday (Friday) and today (Saturday).
Apart from the fact that there was nothing to 'see below', thanks for sharing. You're in a unique position to be able to pinpoint a possible trigger for this new problem that's affecting more and more users. Can you conduct a search of your computer to find files that changed (Date modified) between Friday and Saturday? I've no idea what we're looking for, but it could be security software like anti-virus, anti-spam or special stuff like Trusteer Rapport, updates to device drivers or any other program ...
PS I changed the startup type to automatic - delayed start and that seems to have stopped the pop-up
That's good to know. It means that the conflict is happening early in the boot process. Since the WLIDSVC will only be needed once a program needs authentication, it's not imperative that it starts at boot time - it's quite soon enough after Windows has loaded fully.
Another intriguing factor is that most of those affected (there aren't many) seem to be outside the US, in France, Oz and Denmark, for example (assuming that the East Coast of AU isn't somewhere in Austria). Given a couple of sysinfo logs and product reg key values, it should be possible to identify the rogue software very quickly.