I have a Dell Studio 1535 with Windows 7 Ultimate 64bit, the DVD-RW drive is Optiarc 7640s. I have read that there are a lot of people having problems with that particular DVD-RW drive. The problem is: it is not detecting DVDs; it detects, reads, and writes cds satisfactory. I have used the Microsoft Fix-It to no avail. The only options I can imagine are to clean the lens and replace the drive, but both of those are a very difficult task. I learned, via the service manual, that you would have to remove the bottom cover, the LCD display from it's hinges, the media control center, the keyboard, the Palm rest; which is basically disassembling the entire computer. Any ideas for a solution would be greatly appreciated, thank you.