CDs, simply put, do not come in sizes larger than 700MB. DVDs on the other hand can.
It is just
not possible to fit 2GB of data on a 700MB CD unless the data is compressed. You can fit a bit more than 700MB possibly if overburning, but you are talking in the realm of a few more MB at most. Otherwise, it is just physically and conceptually impossible. Period. End of story.
What johnwill was referring to was that Windows can misreport the reported size of files if those files or the media which they are on are corrupted.
This means either the data was infact compressed or is corrupted.