Erase DVD/RW

What steps do I take to erase a DVD/RW?

Windows should offer this function:

Open My Computer.
Double-click the CD/DVD recording drive. Windows displays the files and folders located on the CD/DVD.
Under CD Writing Tasks, click Erase this CD/DVD-RW. Windows displays the CD/DVD Writing Wizard.
Follow the instructions in the wizard to delete the files on the CD/DVD-RW…

Far better to use your burning software like Nero. Alternatively the likes of DVD Info is a good choice.

DVDInfoPro - best choice!