We've had this issue at the school where I provide support where we've had laptops with the wireless lights on but fn+F1 will not allow you to switch it on or off. The issue has mainly arisen with pupil laptops where we disabled the launch manager.
Therefore, if the fn+F1 is not working you will probably need to reinstall the launch manager, i.e. when you are in Windows and press fn+F1 you should get a window detailing the wireless and bluetooth connections.
If you go to Fujitsu's website you can download the latest version for your particular model of laptop. Run the setup and if prompted to uninstall first do this, then do a fresh reinstall. After reinstalling and a reboot you should find the launch manager is now working correctly and fn+F1 will now turn the wireless on and off.
AdamB, September 2009