Both drives in my comp (GSA 4120B and GCE 8160B) are failing to burn (media is Prodisc DVD-R, Philips CD-R). I'm using NERO 6, and just a few seconds after it starts to burn, it signals a failed writing error. In the both cases, they actually burn a slim ring before the process stalls.

I noticed Nero's buffer bar is low or blank, just before it freezes. Tried DVD decrypter to get some additional clues, but to no avail... Everything looks fine. Tested them on a different machine, both drives responded the same way... What should I do, guys?