I turned on my laptop today to find no internet connectivity. As per usual I went to go reset my modem but found the laptop was not picking up anything else (the light on the front wasn't on either). I tried the following:
Turned off and on via the switch on the front.
Pressing Fn + F5 while it was switched on would cause the light to flash; this did not happen
I looked in Device Manager, which told me the adapter was working. Subsequently I reinstalled the driver.
I disabled and re-enabled in the BIOS. This seemed to do something as when disabled in the BIOS the wireless settings disappaered in Windows.
I've even resorted to reinstalling the operating system.
When diagnosing the problem Windows says no problems, but when looking at the detailed report it says "Radio is off (HW Switch)" As I said before, I've put the switch in every possible combination.
I think it might be a hardware issue, but I just wanted to be sure before I attempt to open the laptop.
If it helps, the laptop is a Lenovo G550 with some kind of Broadcom 802.11g adapter [BCM43XG].
I cannot think of anything else you have not already tried, so I concur it is likely the wireless card has gone bad. However, first find the card, it is often under the same cover as the memory, and make sure all wires are attached well and try it one more time. . .