CD-RW error: There is no disc in the drive. Please insert a writable CD

Dimension XPS T600 running Windows XP home w/SP2. I have changed the "3" to a "2" in the Drive Type Value Data box to indicate that the drive is a CD-RW type. This was done as instructed in article Q316529. I thought this would be all that was needed, since the "3" indicates a CD-ROM that is not writable. In the Device Manager properties, I verified that the Drive is set up to record, and it was working before I cleaned the registers with a free software program. I thought the "3" had come from the register repair operation. The other drive is a DVD-ROM and it has a "3" which I understand is correct. Device in question is a SONY CD-RW CRX 100E. I have tried writing to both blank CD-R's and CD-RW's and get the same error message with either media.