i am using the latest version of nero and a liton dvd burner 16 speed dual layer ,now all of a sudden the burner will only copy at 2 speed even though it is showing 8 speed ,i also done a speed test in the nero tools and it showed 2 speed,anybody any idea,s what is wrong

Have you checked your DMA settings?

how do i do that,please

Through the properties of your ide controller(primary or secondary channel) that the drive in on within the device manager.