CD Player/Burner has stopped detecting CDs

I have a Dimension 8200 running XP Pro.  The DVD-ROM is a LITEON DVD-ROM LTD163 GDH (Drive D).  The burner is an HL-DT-STCD-RW GCE-8400B B104 (Drive E).  The disc detector is Creative Disc Detector, Vers. 1.59.

As recently as yesterday, Drive E took several attempts to recognize a blank disk for burning, but it did do so.  Today, it will not recognize any disk, either a blank one for burning or one for playing.

I've tried toggling the disk detector, including rebooting the computer after toggling off and again after toggling back on.

In addition, both drives will no longer detect a CD-RW.

I'd appreciate any help in resolving these two problems.

DtheD