Open start menu, type "disk management" and click on the link that appears. You can then shrink the volume for C: (if you have space) and create a new volume. This is the simple way to do that. It may seem hard, but it really isn't. Just right-click on the graph in the middle of the screen, select "Shrink Volume" and follow the instructions.

Then, right-click on the free-space on the graph and follow the instructions.