clerkwang 兄說的對...
I use Princo 1x DVD-R and try to burn it as 2x... and it turn out to be... ALL UNREADABLE...

PS. I Burned PS2 game,and not only PS2 can't read, the DVD-ROM also can't see anything...

so... don't use 2x if your DVD-R is 1x unless you tried b4 that 2x is readable (depand on the brand I guess...)