I'm having what sounds like the same problem. It started about a month ago and has got progressively worse. At first it was only discs with a UDF filesystem that were unreadable. Windows sees nothing. Examining them with Isobuster revealed that there were files on the disc, but sector location data was all wrong. Also claims disc is DVD-RW when it is DVD-R. Putting the disc in a Samsung combo drive, it was perfectly readable to Windows, yet Isobuster would claim there was nothing at all on the disc? I found for a while that changing the firmware (to any of the versions I have) would render the disc readable in the 3520. This is no longer the case. I've just burned a disc with just an ISO filesystem. Nero finished the burn, and the autorun started as soon as it had finished. I ejected the disc, reinserted, nothing! I've changed cables, reduced power load on my system, reinstalled Windows XP, all to no avail. Any suggestions? Has the drive partially died after little more than a year of moderate use?