Windows 7 USB DVD Download Tool is a tool developed specially to copy the installation ISO image file that can be bought online in the Microsoft Store, you can copy it to a DVD or USB pendrive.
We can say that it is specially thought for netbooks that doesn't include a DVD unit.
Once you have this file, you'll only have to choose the Windows 7 ISO file and choose the drive where we want to copy it.
Take in mind that USB pendrives must have at least 4GB of free space and the program will format it before copying the image.
How to install Windows 7? Windows 7 USB DVD Download Tool is the answer.