DVD-R/RW Drive Problem

Hi to everyone.  I might as well apologize first of all.  Besides being a newcomer to the Message Board I am rather computer illiterate.  I have a Desktop XPS 400 it is apox 1 year old.  I have 2GB of memory use Windows XP with a video card Radeon X300SE 128MB HyperMemory.  I do have a DVD Burner

HL-DTST DVD+RWGWA 4164B along with TSSTCorPDVD-ROMTSH3525..  I have purchased Window Vista Home Premium but have not installed because everyone tells me they have had so many problems with it.  I also have Roxio and Window Media Player.  I have purchased ICOPYDVDs2 Ultra Edition Downloaded DVD43 from the internet. I am trying to back up some movies I have.  The program reads the DVDs just fine, but when I insert a blank DVD-R into the drive (Memorex DVD-R) it is not recognized and tells me to insert a blank disc.  I even bought another box of DVDs thinking the first might have been just Frisbees.  Please someone find it in your heart to have patience and help this newbie!