okay, i just got my nd-2500a, an external enclosure, and a 50 pk ritek dvd-r’s
everything went together easily, drive recognized, by windows and nero (was 6.0.0.0, but i went out and got the new version just in case, though havent used it yet)
using usb2.0, i made a multisession dvd of 4.4 gigs, and nero burned the dvd no problem, and said “completed successfully”
however, the dvd i made is not recognized in any of my dvd drives, including the burner that made it, a.k.a, windows is not seeing the data at all, if even the cd ?
but if i go to nero and try to continue a multisession dvd, it sees the track and sees the data on the dvd, so the data is there apparently, but if i try to add to the session, i get an “invalid disc” error
so what has happened here ? is the data on the disc ? is it viable ? do i have to do something to make it visible ? or have a made a coaster ? and is there any way to avoid it again ? i want to get my facts straight before i try to make another coaster 
thanks greatly !!!