Mac OSX mouse click no response in login screen

Suddenly My macbook air doesn't respond to mouse click on login screen though mouse move works. I didn't meet this issue before, so did some google and found this nice blog.
http://www.justanswer.com/mac-computers/2w49b-mac-frozen-login-screen-mouse-cursor-works-no-response.html

It provides 3 methods, and I tried all of three, but only worked once. Next time, I open Macbook Air, it stops working again. I have to hit shutdown and restart again using command line, and fortunately I saw a bluetooth device connected (something like Apple magic trackpad). After see that image, I realized that the external Magic trackpad took over the mouse click events from built-in trackpad. I went to garage and found the magic trackpad, then use it to login OSX and disconnected the bluetooth trackpad through System -> Preference -> TrackPad.

Reset PRAM and NVRAM
    Shut down your iMac
    Locate thfollowing keys on the keyboard: Command, Option, P, and R.
    Turn on the computer.
    Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears and before the chime sound.
    Hold the keys down until the computer restarts and you hear the startup sound for three times.
    Release the keys.

Restart in SafeMode
Make sure that the computer is shut down. Press the power button. Immediately after you hear the startup tone, press and hold the Shift key. Release the Shift key when you see the gray Apple and progress indicator. Let the Mac bootup...

Run Disk Utility in Single User Mode :
Turn it off. Turn it back on and this time hold down the Command (Apple) key and the S keys at the same time. Then type the following command...

/sbin/fsck -fy (note the space between fsck and -fy)

If you can't run /sbin/fsk - fy then type only fsk - fy
Hit return and the disk utility should run and let it finish. When it finishes and there is no error, then type reboot and hit return. Let the Mac boot up and see if it is still giving you problems.

Read more: http://www.justanswer.com/mac-computers/2w49b-mac-frozen-login-screen-mouse-cursor-works-no-response.html#ixzz3TGuGYDJO