Yeah the disc is fine.. I've burned over 5 discs too. Here's how I'm setting it up in Nero:
and for burn speed i've tried 2x, 8x, and 12x
the first time i got an error because I did a multisession disc and it said it might not be readable, so after that I did the no multisession.
And when I put in the two discs i've already burned, Nero brings the discs up and shows that the stuff i've burned is there. But the computers won't even recognize there is a disc in the drive if I look at it in windows explorer