I have been experiencing this problem from months now, but did not bother to ask for help. I noticed that the WIFI blue led on my SAMSUNG notebook NP900X3G is always on before logging in to Windows, that is when typing the access password. Any attempt to shut it down through hard (Fn+F12 key) fails. This happens even if the laptop's network connections (WIFI adapter) have been disabled in Windows. It wasn't always like this; after purchasing this notebook, I was still able to disable. Is this normal behaviour?
See if a simple uninstall/reinstall of the wireless network adapter will resolve the issue.
- Go to Device Manager and uninstall the wireless adapter.
- Reboot your laptop and it will reinstall the driver automatically.
- After the reboot observe weather the same problem will happen or not.
- If these will not work, download and install the latest driver there is from Samsung support site.