CD Writing in Windows XP

Hello Friends,

I have Windows XP Professional Editon. I usually write CDs
using the inbuilt XP feature. But, the CD that I am trying
to write shows 832MB whereas the CD itself is of 800MB. I
do have same CD but I am unable to write. The message that
I get is somewhat - data in the disk exceeds and cannot be
written.

But, then how the CD might have 832MB.

Any help on this is muchly appreciated.


regards
David