The Nr Fairy,
Are you using CD-Rs or CD-RWs? What is the brand and age of you car's CD Player?
Do try a different brand of media to see if it makes any difference.
Take Care,
Richard
P.S. spannersatcx, I am always learning. Do me a favor and try swapping your CD-Burners. I would like to see if the problem with burned CDs not playing in your Hi-Fi travels with the CD-Burner or stays with the computer. (I would like to know which it is.)