That's assuming the main drive is labled C.  This also only works for a Windows computer.  What you failed to mention is how she will access information that has been set to be shared.  First off, you want to set a password when your sharing a folder or drive.  You should see a prompt when your setting share settings.  To access a computer that has a shared drive, simply go to network neighborhood, find the computer by clicking on it, and you should be prompted to enter the password you earlier gave, then you have access to the files, you can drag/drop and even save files to other computers.
As someone who knows nothing about networking, how do I network my PCs with a wireless router?