The problem is with the Nvidia software IDE driver that gets packaged with the rest of forceware...
My understanding is that the Nvidia IDE driver (much like the Intel Application Accelerator IDE driver that causes similar problems) is optimised for Apps/Games <-> Hard Drive, which is a very different IDE data transfer situation from Hard Drive <-> DVD+-RW or DVD-ROM <-> DVD+-RW...
As for getting rid of it: PAIN IN THE ASS!
first things first:
NEW Forceware 56.56 drivers:
next: Uninstall all old Nvidia drivers and reboot every time it asks!
Install new drivers, choose to NOT install IDE SW driver.
Check in the Device manager to be sure that the the Nvidia IDE driver is not there. If it is, check Add/Remove Programs, there may or may not be the option to remove the IDE driver in there...
I haven't pinned down the exact process for getting rid of that bastard; I've done it three times so far and each time it took a mess of uninstall reinstall reboot remove reboot blah blah blah... if you fight with it for long enough, it WILL go away.