Why don't you simply have a new DVD bundle(25?) and allow the ease of mind that you'll have more than enough. Plus, you'll have spare DVDs for later as the need arises. In most cases I find 4 DVD or less will do, but as PCs come pre-loaded with whatever s/w bundle(s) it may ask for more. Most new DVD drives will access CDs as well. You want DVD +/- variety but find + works best.