Format a DVD+RW

How to get the DVD drive to recognize that there is a DVD in it and not a CD.

Have been trying to write to a DVD+RW in WinXP with Nero InCD as the format tool. Files are ready to write yet the message indicates that a CD is either full or is not the correct disk.

The disk in the drive is a DVD+RW that is fresh out of the box. If I try to format thedisk, the drive seems to only recognize that the disk is a CD.

The DVD drive is a Benq DW400 and MRW is not recognized.

What is the fix??

Secondly, when looking at a DVD disk in explorer, the disk is always full. Why does it not read the 4.7gb and indicate that is is unused?