I have a Toshiba Satellite A35 that I use as my traveling laptop. I've been backing up my data files to an external DVD burner (HP DVD 740), and also have an external CD burner (ATAPI CD-RW) attached through a D-Link USB hub. A couple of weeks ago the write functions on both the external DVD and CD stopped working. I can still read from discs, but not write. I hooked up an older TDK DVD burner and have the same problem, it reads but won't write. Given that all 3 used to work and I haven't made any changes (other than updateing virus signatures), what might cause them to stop writing, and what can I do about it other than buying a new laptop?