With the release of Vista, Windows 7 and Windows Server 2008, Microsoft has removed the standard ActiveSync USB transfer program. They now use a Suite of software for Windows Mobile Devices. This new suite is called “Windows Mobile Device Center”.
The software can be downloaded for free from Microsoft and must be used in order to connect your USB Handheld Devices to your PC.
For more information, and the page to download Windows Mobile Device Center, follow this link.
Note: Please be sure to read the entire instructions on the Microsoft Website. Also older versions of Windows handheld operating systems may not be supported. The info page linked above contains more details on this.