4x-10x

Dear Friends, I'm using this Samsung's Cd-RW [40x-12x-40x] SW-240B since last 2.5 yrs, along with Nero Burning Rom 5.5. Had no problem, but since last few weeks I'm facing two queer problems: 1. CD-Rs r not being burmed at a speed more than 24x and CD-RW r not being burned at more than 4x ...