About 3 months ago I was having no problems with the burner, but recently some disc would not work. I have a 100 spindle of memorex discs that came with a note that said to update firmware, which I did and they still do not work. But I buy a 20 pack of memorex discs and they work. I emailed memorex and they sent me a new firmware and it doesnt even work. It will not work with Nero, D-decrypter, D-shrink, magiciso, etc. so its not jus8t one single problem. For Nero it says illegal discs, I'm up for buying a new burner but would rather not, thanks for all help in advance.
If your other Memorex media works with the burner, then it appears that the 100 spindle is junk. Try some Verbatim or Taiyo Yuden.
Well, I gave you a suggestion. If you don't want to try it, than so be it. It is a way to narrow things down. Have you tried uninstalling your secondary IDE ATA/ATAPI controller, in Device Manager, then rebooting?