There are some simple and easy solution around which we are overlooking. You see now-a-days we all have multimedia keyboards which contains different key-binding to different programs. Some keys are set to open your default browser some are assigned to volume and some are assigned to open your emails. So at the very beginning we need to check the behavior by removing the multimedia keyboard from computer even the multifunctional Mouse. The cause may arrive from there only. In my case it happened. I removed my keyboard and attached another keyboard and the problem was immediately gone. I took the keyboard and installed at my Father's system to check if the same problem happens to my Father's system, and believe me that problem replicated itself there in my Father's computer. So I am confirmed that the issue was causing for a faultier keyboard.
So try to do the same as I did. Check if the problem remain same or not.
Thanks
LASMOND