DVD Discs

Hi, I have been trying to burn / copyfiles etc to mu Sony DVD
Burner but have struck a problem. When I insert a blank DVD
and I check the space on the disc it always comes up that there
is used space of 2 gb and there is insufficient space on the disc.

I have tried DVD-R, DVD+R & DVD+RW blank discs with the same
result and therefore i am unable to copy any DVD’s.

Does anyone know the answer to my problem