cdr

[Dave Boothroyd]

Physically they are still on there, but when you recorded the new data, your PC wrote a new table of contents which did not include them, so they are ignored when you play the CD.
In answer to your question about whether you can re-use 'coasters', the answer is yes, mostly. The most reliable way is to use Adaptec (Roxio) Direct CD and configure them to work like a Windows drive- they you can just drag data files, including WAVs to the disk icon and save them on CDR. Audio CD burning programs regard closing the CD as the end of a "session" and tie up all the loose ends before ejecting the CDR. Direct CD allows you to leave it open and add more stuff later- but you have to tell it if you want to configure the disk to play in a normal CD drive as opposed to a CD burner drive.
Our less talented students keep me well supplied with 'spoiled' CDRs!

[Jack Stoner]

The session was left open. You have to "finalize" the audio CD in order to play it on most CD players, except a PC CD player.