How to Extract an NRG File
An NRG file is a CD image file encoded in the .nrg file format. This format is a proprietary format used by Nero Burning ROM software, made by Nero AG. However, despite the proprietary nature of this file format, a number of free software programs can read these files.
Download a free software program capable of reading .nrg files. One such program is Alcohol 52%; it's a free and powerful tool that can be used to read, create, copy, and burn CD image files (see Resources).
Install the software. For Alcohol 52%, the first time you run the program it will create a virtual CD-ROM drive, which you can then use to mount CD image files (which has the same effect as if you had burned the image file onto a CD, then inserted the CD into your computer's physical CD drive).
Open the .nrg file with the software. For Alcohol 52%, you can accomplish this simply by mounting the .nrg file onto the virtual CD drive you created when you first ran the program.
Open the image file with Windows Explorer and copy any files you want from the CD image file to your hard drive.