I've have several data DVD+Rs, compatible with my drive, that I have burned files to. Roxio nor MS Vista Explorer will let me add more files to them. I don't recall finalizing them. I can burn to my CD+Rs though.
Under Properties for my drive it shows my DVD+Rs are full: example- one with 256mb and no free space.

Did I format them to write once and finalize so other files can't be added?
Did I answer my own question?

Thanks.
Beau

In no way do you want to format a disc unless you are going to use it for Drag to Disc,which is not a good thing to do.
What you should have done to make the disc appendable is when you burn it make sure you uncheck "read only" in the burn options.Then when you go to add data make sure you "import" the previous sessions first.

Thanks for your help.
Beau