There are several ways to drag and drop.
(1) The best way is to use DriveHQ FileManager client software. It is extremely easy, reliable and efficient. It is also seamlessly integrated with DriveHQ.com website. You can access a lot more advanced DriveHQ features, esp. share, publish, version control, folder synchronization, etc.
(2) You can also use regular FTP service for drag and drop. For more info, please visit:
http://www.drivehq.com/ftp/
(3) You can use drive mapping; for more info, please visit:
http://www.drivehq.com/mapdrive/