You can prevent device installation in Windows 7. There have been media reports of some companies physically destroying USB ports to prevent data from leaving the premises on USB devices. A better solution is to prevent installation of USB-based storage devices at the operating system.If the device cannot installed, then data cannot be transferred to it. You can also control removable storage as a class of devices.

• Device Identification
• Device Installation Group Policy Settings
• Removable Storage Group Policy Settings