How can I erase DVDs

[Bobh]

I have backed up my computer on DVDs.  I have several of these but only want to save the last one I made.  I want to erase the old ones and use them again.
When I put a new DVD in to run a backup a panel says that it must be formatted and that will erase every thing on the DVD.  There is nothing on it because it is new.  If I put a DVD in  that has a backup on it, the panel says that there is already a backup on the DVD and refuses to run it.  How can I get it to erase the DVD and leave it clean so that I can use it again?   Thanks    Bob

[Carbon Dudeoxide]

Are they DVD-RW's or DVD-R's?

[Dias de verano]

Are they DVD-RW's or DVD-R's?

A good question!

[Bobh]

I forgot to tell you facts.  I am running Vista Home basic on an E Machine.  The DVD package says  DVD + R.  The computer panel says I am using it in  "DVD RW drive (E:).   Thanks for the replies.   Bob     

[Carbon Dudeoxide]

There's your problem.

The DVD's are DVD-R's or DVD Recordables, not Re-Writable. They cannot be written on a second time, only once.

[Bobh]

Thank you for the explanation.  I just went into Best Buy and bought what they told me I needed.  No big deal.  I don't plan on making a backup very often and the DVDs are not expensive.  I'll just discard the old ones.   Thanks again.   Bob

[Carbon Dudeoxide]

Anytime.