|.NRG is Ahead Nero's proprietary disc image file format. Even though the standard many people are familiar with is .ISO (ISO 9660), there are several other propietary formats out there as well - depending on the software, see below for a few examples.|
- .BIN/.CUE (CDRWin, Alcohol 120%)
- .CCD/.IMG/.SUB (+ .CUE optional) (CloneCD, Alcohol 120%)
- .BWT (BlindWrite)
- .CDI (DiscJuggler)
- .MDS/.MDF (Alcohol 120%)
Normally these images are primarily meant to be mounted using a virtual disc tool and a very popular one is Daemon, however if you have Nero installed, you can enable an image drive from the program and also mount it that way.
If you do not want to mount it, you can use programs like MagicISO, PowerISO, UltraISO and so on to open the image and extract or manipulate the contents as you wish, hopefully you've caught my drift.