How do I convert a DVD of something, which is an .ISO file to AVI? Which program do I need to download? As i’ve tried lots and they don’t seem to support this conversion. 
You can free download this video converter, which can convert ISO to any video formats.
Follow the guide of Video Converter to do
ISO is an archive file of an optical disc. It covers all the data of files contained on the archived CD/DVD, or any other disc format. However, ISO is not supported by most players, tablets, phones and video editing software. So, convert DVD ISO files is really necessary. To do this, you need the help of a DVD ripper that is capable of converting DVD ISO image files.
Here Brorsoft’s DVD Ripper is highly recommended as the best DVD ISO converting program to help you get your work done.
Try MacX DVD Ripper Pro, which supports DVD disk and ISO image flawlessly.
With this ripper, you can easily have your DVDs to be converted to AVI, MP4, MOV, MKV, FLV, WMV, etc formats for playing on your Mac or PC, even on your iPhone, iPad, Android, Blackberry portable devices.