Actually, I would respectfully (but completely) disagree with most of the above responses. There are a LOT of people who have had problems trying to have both Roxio (certain versions) and Nero (the last three updates, since last fall) installed at the same time. Some versions of Roxio have some drivers that cause lost of problems with the latest versions of Nero, and this has been widely discussed on most of these forums. In fact, those same drivers can cause certain drivers used by the actual DVD burner to error out, usually with a false “illegal disc” error. Those people cannot burn at all, no matter the software, because Roxio is installed on their system – although it is not running at the time. Lite-On had a note at their web site about this. This is most common for those with Lite-on DVD±R Drives, by the way. But, a lot of others have had the Nero / Roxio conflict.
Do a search, you will find this discussed. I always advise trying to get rid of the Roxio (even though it can be a pain to completely unistall), for the above reasons. Yes, you MAY be okay. But, enough people have run into this conflict that you might be one of the afflicted.
For those interested, here is a thread discussing the conflicts with both Nero and DVDDecrypter as burnng tools:
Click here to visit details of the conflict, and how to uninstall
Sorry to be so disagreeable, but my friend had this conflict, and it cost him more than 40 straight DVD coasters before he learned of this. After he uninstalled his Roxio, he has had nine months of coaster-free bliss.