CD-RW will not "drag and drop" from Windows Explorer

Anyone........ My CD-RW will play MP3s, install software from a CD, play
commercial audio CDs; however, when I put a blank CD-R into the drive, I
can't "drag and drop" files onto it. With the blank CD-R installed in the
drive, Windows Explorer says the drive is "not accessible." My system is a
Dell with Windows XP SP-2.

First, is this normal? If not, what can I do to get it right. I believe it
used to work fine with drag&drop. Please comment, thanks.

EW