Bluetooth laser mouse missing features in Win 7

[Joan]

I have a Lenovo Thinkpad T500 on which I did a clean install of Windows 7. The bluetooth laser mouse did not work so I downloaded the driver from the Lenovo site. The mouse works except, I used to be able to hold my finger on the control key and wheel the mouse to enlarge or decrease the display. That feature has gone and I would like to get it back. Can anyone help?
Thanks,
Joan