how do you convert cdi or nero files into ISO and what Is best to burn them??

[love me hate]

I have tryed everything i am getting "cannot read data layout now" from disk juggler and nero cant find my cd burner so alll it dose Is save a image instead of burn, If you can help fix these probs or tell how to bunr a ISO file please let me know befor I go out and buy a new cd burner.
Thanks