My NEC-2500 DVD RW won't read any commercial dvd's. It reads cd-r's fine but isn't recognizing dvd's. I've been using this drive to burn backups of commercial dvd's with "dvdshrink" for the last year and have had no problems at all. Except for some reason last month our encoding speed was slowing down from 4,000 kps to 1500-1800 kps. I read some forums about improving the encoder speed and they suggested to change the transfer rate from "plo" to "dma" transfer. I tried to do that by selecting "dma transfer" through device manager with no luck. I than tried to uninstall the "ide/ata controllersrimary ide channel" and rebooted my computer. Immediately after this the problem with my dvd writer started. According to device manager all drivers are working properly for the dvd rw, primary channel. Please help, any suggestions? my current sys: win xp, intel pentium 1.9 ghz, 1 gig memory, 80 gig hard drive 2mb buffer, NEC- 2500-dvd rw.