Inspiron 15R - Mouse focus keeps on changing

I just bought a Inspiron 15R (N5110), running on Windows 7 SP1 64 bit.

This issue really driving me nuts and frustrating. Unfortunately, I can't find any workable solution yet.

When I typing my email or documents, out of sudden the focus of the mouse / cursor can just end up in other area.

It causes me to correct my sentences again and again. This one really kills my productivity

What's the actual issue ?

When I have time later this week, I'll record a video to capture the error and show you all.