If you connect the camera to the computer with the USB cable and the memory card pops up as a new external drive, you can open it and copy the photo files to the hard drive manually, usually from the card's "DCIM" folder.
If the computer does not recognize the connected camera or offer to import photos, check the manual and install the camera's driver software.
If the computer has a built-in memory card reader, or you buy an external USB card reader, you can stick the camera's card in the reader and copy the photos without connecting the camera.
Some discs include software for processing, editing and organizing photos imported from the camera. If you already use a program like Adobe Photoshop Elements, Google Picasa or Apple iPhoto to import pictures, you do not have to install anything new.