Yes I can. No problems there.

Okay, I just did a clean reinstallation of my system, and that thing is still behaving the same. I know it's not an outright hardware problem because wireless and bluetooth do actually switch off or on after I set the button to either position and then restart the machine, so we already know that the button itself actually works. It's what's causing it to not swtich the adapters on or off immediately that's daunting.

Again, I can still swtich both adapters on and off using the Fn+F8 tile. So although actual functionality isn't hampered, I do find it strange that the physical button should behave the way it is.

Any theories?

Okay, good news: issue resolved (at least for now.)

Yesterday, I happened to flip the U500 over to see if it had a receptacle for a SIM card (it didn't; there's a place for it under the battery, with an embossed graphic and all, but no actual WWAN module is installed.) So I noticed the small plastic cover next to the larger one under which the RAMs would go, right where the wireless/BT switch is. It provides access to the Wi-Fi module.

So I decided to unscrew that and take a peek inside. I just took out the wireless module to check for any physical damage and put it back in, and shined a light on the sensor and switch mechanism. Everything seemed to be in order. I screwed the cover back on and started the machine, and the switch worked as it should again! I don't know if it's moisture or accumulated dust or anything else, but it looks like all it needed was a breath of fresh air! Happy camper here.

Thanks for all of your helpful replies.