here the answer of your problem:
It's only because of application software, not because of hardware problem!!!
this problem happen because the setting in your antivirus/protection application software.
It can be because the antivirus application is still unstable.
You may check to setting at antivirus application (here is ""McAfee Security"), go to wi-fi security setting, turn it off. Then you may exit the antivirus application. Try again to turn on your wi-fi. Then your wi-fi get normal again......thanks God....
Regards,
Genius Man