I tried to upgrade my Sony DVD RW DW-D56A's firmware, but while I was trying, my computer froze. So I decided to reboot. (I know it shouldn't be done, but I have waited for like hours, looking at the freezing, irresponsive laptop.) After the reboot, my computer still recognize the DVD, but the DVD wouldn't read any CD at all.
I had tried for several time more with each time, a newer version of firmware. All the time, my laptop froze, and I still got the same result.