Backup program disks
In order to install programs, you have to have either the downloaded install program (if you downloaded the program from the internet) or the program CD. Most programs are installed from CDs. If you loose the CD, you will not be able to install the program until you either find the CD, borrow a CD from a friend or purchase the CD again.
Most companies if not all will not replace the CD if you loose it or the disk gets damaged. In order to replace the CD, you will have to purchase the program all over again. If it is a game CD, you may spend $30 to $80 to replace the CD. If it is a program CD, such as Microsoft Office, you can spend $100 to $600 (or even more) to replace the CD. That is hard to spend money on when you already have the program.
After a program gets installed, you will not need the program CD again till you either reinstall or update the program. It might even be years before you need the CD again. In the meantime, the CD might get broken or misplaced. Lost CDs is the biggest complaint I have heard. Just about every time I assist someone with a reinstall of their operating system, the customer is unable to find a CD of a program they have.
To protect you from experiencing this issue, create an ISO image of the CD. Most CD burning utilities have the feature to create an ISO image. I know Roxio (now called Sonic), and Nero has the feature. In Roxio, you select the copy feature. In the copy feature, you select Save image to hard drive. you then choose where you want to save the image, give the file a name (one that you will recognize and then you start the process (Roxio defaults to the extension of .gi, so change it to .iso before you start the process). In Nero and other burning software, it may be similar steps but I don't have the software available to tell you.
Once you create the image, copy it to a second location as well in case the first location dies. If you saved it to the hard drive, then burn the image to a CD as well. That way if the hard drive dies, you will still have it on a CD. If you loose the CD, you will have it on the hard drive. My suggestion is to have two external hard drives. Save the files on the first external hard drive, and backup the contents of the first external hard drive to the second external drive. This will keep your drive C clean, your data will be on an external drive (which will allow it to be portable. You can carry it with you to other computers if you wanted to), and that drive will be backed up to a second drive in case the first one dies.