Whether it's with the WinXP CD wizard or with RealOne Player, the problem is the same: once the CD is written to, the total size of all the stuff on it is the "actual" size of the CD. Today, after burning just 30 MB of MP3s from MP3.com, I find out that my 700 MB CD-RW has no space free. No warnings or error messages, just a shrinkage of space.
Searching compaq.com did no good; they hadn't any drivers (or fixes that I could find), and getting direct support from them is like pulling teeth from a piranha. Is there some way to get this problem fixed?