So here's yet another addition to what seems to be an ever-growing list of drives behaving badly. I've got two DVD drives, neither of which are working properly in 7, the main one being a Lite On (Atapi DVD A DH16A3L) SATA drive. It's a DVD +/- RW Dual Layer that was working perfectly 2 hours before I installed (upgrade) Windows 7 Ultimate (32bit). The drive is recognising and playing CDs but DVDs aren't showing up when I insert them and I'm getting the popup message to "Insert a Disc" when I click on the drive icon. Oddly enough, I can no longer boot a DVD from the drive on Startup since installing 7. The drive itself is showing in BIOS, and all seems normal (at least to me) in DiscInfo, although I'm not sure what "Lock Detected" means or whether it's relevant. I've already tried disabling Integrity Checks, I don't have Upper or Lower Filters, uninstalled Nero 9 and PowerDVD 9, don't have iTunes or anything like that. I've also removed the drive (both physically and by uninstalling in Device Manager) and had no luck with either. I also ran WinASO Optimizer after removing hardware & software but to no avail. I've also tried to put in a working second +RW drive (this one an IDE drive) from a machine running XP that's doing exactly the same thing in 7, i.e. not recognising DVDs but playing CDs. I spent the last three hours reinstalling 7 but nothing's changed. I'm stumped and would appreciate any help. Thanks in advance.