Thanks for your replies Johnholl ans Sparkeykev.
I haven't managed to get my computer reading to work yet but I'm hoping that I will get it to work with what you suggested. Site looks excellent and I will read the content.
BTW, I found what the problem was on my car. As I couldn't get the codes to come out of the computer, I started examining visually everything I could. Turned out my O2 sensor behind the cat converter was broken in two with the wire hanging loose. I then recalled I had hit a tire debris on the highway the day before. I managed to replace the sensor. Of course I had to struggle with removing the old one as it was seized in place. Hey if you run into engine light on, make sure you do a visual of obvious components and if 'luck' is on your side, it may be something obvious !