You do NOT need to uninstall the driver prior using DDU.

It is best to exclude the DDU folder completely from any security software to avoid issues. Make a backup or a system restore (but it should normally be pretty safe). The tool can be used in Normal mode but for absolute stability when using DDU, Safemode is always the best. If you have problem installing older driver or newer one, give it a try as there are some reports that it fix those problems. As with any tool of this kind, we recommend creating a new system restore point before using it, so that you can revert your system at any time if you run into problems. The current effect after you use this driver removal tool will be similar as if its the first time you install a new driver just like a fresh, clean install of Windows. The AMD/NVIDIA/INTEL video drivers can normally be uninstalled from the Windows Control panel, this driver uninstaller program was designed to be used in cases where the standard driver uninstall fails, or when you need to thoroughly delete NVIDIA and ATI video card drivers. Display Driver Uninstaller is a driver removal utility that can help you completely uninstall AMD/NVIDIA/INTEL graphics card drivers and packages from your system, trying to remove all leftovers (including registry keys, folders and files, driver store).

Ddu install