The simplest way to copy data between drives is to copy-paste files using a file manager, such as the default File Explorer application in Windows. You can take advantage of the Homegroup feature in Windows 7 and above to copy-paste between drives on your home network. When this is infeasible, use an external hard drive or memory stick to transfer files between the separate computers.
To copy-paste a set of files, first select the files you wish to copy, and hit the "Control" and "C" keys. Then, navigate to the drive you are copying data to, and hit the "Control" and "V" keys. If you are moving a lot of data or many small files, the transfer could take a long time. A guide that graphically illustrates how to do this is available on ComputerHope.com. DigitalCitizen.life provides a guide for setting up Windows Homegroup. After setting this up, you can copy-paste files placed in the default Pictures, Videos, Music or Documents folders to other computers on the network.
For drives in separate computers that cannot use HomeGroup, use an external hard drive or USB flash drive. Plug the external drive into the computer with the data you wish to copy, and copy-paste that data onto the external drive. Then, plug the external drive into the destination computer and copy-paste the data on the external drive over to the destination drive.