I run windows 7 and when I went to use my old Wacom tablet today with 4D it would not work. In fact it would not work with any software on the computer. It had been working fine with the windows 7 driver previously. In the end I uninstalled all reference to it via the add/remove programs tab and then restarted the computer.
When I attached the tablet the computer said that it needed a driver so I let the computer search. At the Wacom site it asked me which tablet I had. Unfortunately my original tablet, a Volito, is no longer listed. The selection that will work if you have this older one is DFT 521. Select this on the left hand panel and your operating system on the right. I selected Windows 7 and it produced a window that said I needed the new 5.2.1-6a that was released on March 15th this year. With this downloaded and installed my tablet and pen are now fine.
As at the 5th of April the direct link is http://www.wacom.com/downloads/drivers.php
If you experience problems this may be the reason why.
Author of Husqvarna, Pfaff and Sewing Tutorials