Windows 7 - 'w' key is not responding

Helo 7forum.I am facing a strange problem. 'w' key is not responding at all frm my keypad. At the same time double clicking donot work after a reboot. But double click work if i press left click button or if i click on screen (cursor) lock key on keyboard.I m confused,irritated,saddened n facing a lot of problem for this. I m using Windows 7 ultimate SP1 32bit in a sony vaio laptop.Pls help me suggesting a solution to my problem as soon as possible. I cant remember of doing any wrong doing or install-uninstall any soft which can creat such problems.