why doesnt some games work??

[kelly karate]

I have some games in cdi format which i converted to nero image...
then burned them with all the right settings....
but they wont load on my dc!! what could be wrong?
ive tried using the bootcd too, but no luck...
i use quality dics so that cant be the problem
the games were toy commander (echelon) and virtual on II (both thru edonkey...)