DVD-R won't read
Hi, I have a USB Sony external DVD-RW 16x attached to my system. It suddenly stopped reading DVD-R and DVD-RW media *but still burns fine* in both formats. The company who sold it to me say this is impossible, and the reading problem must be something to do with dirty disks or the set-up of my PC. But I've tried everything, and it still won't read - even the discs it's burned itself, which read fine elsewhere. Anyone have any ideas? Should I just insist they take it back?