Try this...
1. Go to "Start" and in the search box type "Change mouse settings" and then click on that in the list.
2. In this new window click the "Device Settings" tab and click the "Settings" button on that tab.
3. On the left side of the screen you should see a list of options with checks next to them. Uncheck the "Pinch Zoom".
4. Now click "Apply" and then click "OK".
5. You can now close both windows and the "Pinch Zoom" should be turned off.