Some of left number key, win key, caps lock, shift do no work

Hello,
some of the left number keys, window key, caps lock, shift and tabs keys of the sony vaio sve15125cnb are not working.
i tried troubleshooting. everything was perfect.
i tried uninstalling keyboards in device manager. no positive result.
i tried some short keys magic. but failed.
though onscreen keyboard is functioning perfectly, some keys of the physical keyboard is not working at all.
please help.
thank you.