This just happened recently. My drive is more than one year old so I can't RMA it. I've been using various CodeGuys firmwares for sometime. Currently the drive is running CG5J. It seems the problem is mainly reading pressed cds, and some burned ones. When reading cds the drive makes a loud whirring noise. The drive still burns dvds and reads them fine without the noise. It also reads some burned cds fine without the noise as well. It seems the more scratched the cd is the more likely the drive will fail to read it and the more likely it is to make this noise. Obviously if the cd is scratched it will be difficult to read, but I have a dvd-combo drive that in the past could not read cds as well as the 451S that now has no problem reading some pressed cds that the liteon drive can no longer read. I was just wondering if anyone else has had simmilar problems, and if they have any suggestions for fixing the drive.