It sounds like your friend might be using some software which came with the camera to transfer her files. (Simply copying them to her PC in the usual way shouldn't delete them). She can either investigate the 'preferences' settings within that software or, far simpler, abandon it altogether.
All she needs to do is open a window displaying the contents of the folder (such as 'My Pictures' where she wants the pictures to go, ensuring that the window only takes up part of the screen. Then she should put the card into her PC's card reader and double-click on its icon until the image files are visible (so that she's now got the two windows side by side). Then, in the second window, select Edit>Select All and drag the files across into the first window. (If that still MOVES the files, rather than COPYING them, she can - after selecting all files- right click on any file and select 'Copy', then right-click in the other window and select 'Paste'. That will definitely leave the original pictures on the card).
Chris