have you updated the firmware if so was the drive working ok before this or not, you could have a bad firmware image.
If you are using an illeagal copy of nero we found that after a time it would start to play up, we thought it was an update sent down, or they had detected the copy and tried to shut it down, trying other burning program may help but nero starts parts of its program up when you start windows and runs them in the background, so you could uninstall nero with the uninstall tools on nero site, reboot and then try other program as a burner, also uninstall the other program you use.
Why? you need to see if it is a hardware problem or software, an easy way would be to take the burners out and put them in another pc to test, you could also try burning none copyright stuff, make a data cd/dvd if its burning them from nero or other program this will help you have seen its not hardware but software, then you have to work out what part of the software or which, nero 7xxx and 8xxx do have problems, plus your using it on 64bit windows not alot of program work well if at all with that be it xp or vista, thats why there have been few uptakes of it. it could be codex or a plug in for nero, even the copyright remover prog could be the problem.
i used to use anydvd to take copy protection off things, this would work great, then stop, you would end up with loads of coasters. due to update even if auto update is turned off.
recap, you need to work out if its hardware or software, it could be connections on back of drive or motherboard, you could try unpluggin them and repluggin them, when system is off, (at your own risk), you could uninstall software, one at a time then test a new burning or old program, use a dvdrw/cdrw, see how it goes.
there is a limited number of burns you can do it may be xxxxhours or disks before the laser goes, i have friends that use the drives up 2 every 3 months, with all the burning they do. it could even be windows its self.
I did come across the same thing on a dvdrw it turned out to be a spider, god knows how it got in the box, but it caused the drive to do the same plus errors, the spider was riding the lens head back and forth, and its legs would sometimes block the beam.
you could also try lens cleaner, as from the number of systems i have fixed dust is the main problem.
anyway something for you to think about and try.
by the way if it is an illegal copy of nero we also found that it uninstalls ok but when you go to reinstall it will not allow it saying you have it installed already or after it does install it tells you, you have an illegal copy. the program leaves something on drive like most others do, could be in windows or hidden, i ended up going back to nero 6xxx without any problems, i think it works ok with vista 32bit, well it did in beta test of vista and RC tests.
i use xp and vista very little now, i have a mac, and linux system. but still build and sort systems out all over the place with windows on.
have fun

overlord is a good game for 360, fable 1 for xbox works on 360 and can be downloaded from xbox live fable 2 is out soon,
h**p://games.teamxbox.com/index/xbox-360/by-genre/18/

it has lists and you can set the genre ie: rpg