Can't use Nero DVD Speed on NEC 2500A! Help?

I’ve burnt a few DVD movies using DVD Shrink + decrypter. These DVDs can be checked with Nero DVD speed using the read test.

However, more recently I have burnt a DVD with folders and files in it (backup of personal files). The folders and files were just dragged and pasted unlike the way I burnt the movies. For some reason, Nero DVD Speed won’t do the read test! Anyone know why? Should I be worried?

What do you mean “dragged and pasted” ?
What program did you use to burn the disc?
Windows does not support built in recording or drag and drop for DVDR discs.

Can you view the alleged files on the disc in Windows Explorer?

I meant Roxio drag to disc (just checked again). It’s Roxio 7…and always running in the background. I believe Windows XP has association with Roxio for CD/DVD burning?

Yes, I can see all the files in explorer.

I apologize for crossing-posting…didn’t know that rule. I didn’t know where exactly to post because I don’t know if it is the problem with software, hardware, or media.