Ok, here is the situation:

I tried to play my Ayumi Hamasaki Complete Live DVD set with my Sony DRU510a. Its a 4 discs set. At first, the drive was able to read disc #1 and #4. But now it cant read any of them. When I double click on the drive, the folder is empty. My normal dvd player can play these discs fine on TV. BTW, there are region 3 discs. Any suggestion?

ps: firmware is 1.0f

nvm, its working fine now, after i reboot the pc.