Daemontools is a software that installs a virtual CD/DVD drive that (for Windows programs) behaves just like a normal CD/DVD drive. But instead of using a physical CD or DVD it mounts a CD or DVD image. You'll need this in case you don't want to use the CDs or DVDs. On the one hand, you save yourself from using the blanks for backups and the inconvenience of having to burn a copy-protected medium. On the other hand you need the hard drive space for the image permanently. Another advantage is of course that you don't have to mess around with disks, but can have everything on your computer. And of course it works faster and there are no more signs of wear and tear on the original.
DT can be obtained here. Beware, the newer installers will not work any longer after a certain amount of time has passed. For private use the license is free.
The installation is actually mostly self-explanatory, except for one small problem: For a few years now, they have been thinking that they need to fool you with third-party software (i.e., mainly software that you don't really want). So when you install the software, read carefully what you confirm or accept. In the worst case you might have a zoo of useless software on your computer. It's also possible that the virus scanner strikes during the installation, because this stuff is first unpacked somewhere before the actual installation. And of course a scanner running in the background notices this and may strike because of adware. If you're not sure, first upload the installer to Virus Total and see what it thinks about it. If you only get stuff like OpenCandy, you're not really in danger. But still you're having the trouble of getting rid of it. In this case google how to get rid of the program in question. In the case of OpenCandy, like this.
With the newer versions, DT automatically creates virtual drives when you open an image via double-click and inserts the image. You can also manage this in a more suitable way by using the tray icon. There you can remove and add drives and change virtual media.
There are cases where games are known to interfere with emulation and burning software and then strictly refused to install. Daemon Tools also belongs to this group of software “unpopular” for game manufacturers. So you may experience problems with this.