You must go to "Start" and then choose the "Control Panel" menu, then go to the "Device Manager" icon. The Device Manager application were appears in 3 seconds to open. You need go to the "Action" menu and then choose "Add legacy hardware" menu. Once an Add Hardware wizard will appears in the dialog, click Next and then go to an another select "Install the hardware that i manually select from a list (Advanced)" option menu to find out on how to install a 3D Vision Driver for Windows 7.
Example picture on how to install a 3D Vision Driver: