You added a 2nd monitor in your pc but you have placed the second LCD/monitor on the left hand side where the mouse enters it from the first monitor from the wrong side: that is, from the right hand side?
If you are placing the second monitor on the right hand side, then the mouse should enter it from right side of the first monitor. But how will your PC know about the position of your 2nd or 3rd etc monitors?
The solution is simple:
Connect your Primary monitor to display port 1 and the other monitor to the port 2:
Place the second monitor on the left, right or top side: it is your choice to make : )
Now go to desktop and right click: In Win7, click on Screen Resolution:
Now you will see a window where Two Monitors will be shown: first of all, click on Identity in order to find out which monitor is 1 and which is 2:
Now move your mouse over to the monitor icon that says 2: left click on it to grab it:
Now you can move this monitor to any position. You can move it to right, left, bottom or top of the Main Monitor.
Move it to the right position and then click on apply or ok: