Problem with the keys 'Backspace', 'T', 'Left - Shift'

NEED HELP

Seems like certain keys of my keyboard are malfunctioning. Here are the few discrepancies I noticed:

1. on press of Backspace, its disabling the touch pad.

2. while working in windows office application (word, excel) on press of 'backspace' OR 'T' it opens the spell check. This is so irritating and left 'shift' opens up the help side bar.

3. In firefox, left shift key opens up firebug. 

But these keys works perfectly fine in all other applications. I have tried re installing my operating system and also made sure that my system is virus free. I am using US keyboard layout.

If anyone is aware of this issue please reply with a solution. Thanks in advance.