Ah. You want to use the disk image and not transcode it, then? It does help if you state clearly, what it is that you are trying to do.
In this case, you do not need to burn the image to optical disk. You simply want the image file to exist somewhere that you can find, on your hard disk. Make this so. If you already burned it and erased/never had the image on disk, then just copy the .iso file from the cd or dvd, to hard disk.
You should use Alcohol 120%'s virtual drive menu to mount that disk image file on your hard disk, in the new virtual drive. This is the electronic equivalent of putting a physical disk in a physical drive.
Use the Virtual Drives menu to create at least one virtual drive, if you didn’t elect to do that when you installed Alchohol. That should get you to the images list. You will need to add your new image to the list, so right-click on a blank space in the image pane and select “add images”. Navigate to where you put the .iso, select and add it.
Now right-click on the image name in the list, and select “mount on device” and pick the virtual drive you want to mount it on.
Once you have mounted it, you can access the virtual drive exactly as you would a physical drive. Drive F will be present in Windows Explorer, and it will have the content of the disk image that was loaded. If this is software, you can install it from Drive F:. If it is data, you can copy it from drive F:, or just use it from there without copying. The one thing you cannot do is change it – you can’t add or delete files from the virtual drive, because that would involve changing the underlying image.
You need different software and a different approach, to do that.
When you have mounted the image into the virtual drive, you may have options to select about what you want it to do in the future. If you want the virtual drive itself to still be there next time you reboot, then your virtual drive software has to be set to start automatically. If you want the disk image you just loaded to be available too, then you must tell the disk software to automatically mount the image.
You can use Alcohol 120%'s virtual drive feature without using any other feature. You can change to other virtual-drive software, like Daemon Tools. You probably should avoid running two at once, because this can get very confusing. (“Drive H. Now, is that Alcohol’s virtual drive, or DT’s?”)