I´ve had issues with the CD writer on my BP6 (on the standard IDE) now and then. Symptoms: Nero 5.xxx would sometimes report "wrong media speed" on a write attempt. Sometimes the 12x writer would burn at 4x, sometimes at 12x, sometimes not at all.
One reason for this have been conflicting burn programs. In my case, Nero, Feurio and WinOnCD did not get along nicely. Most burn programs seem to install their own drivers. CDROM emulations seem to be especially dangerous.
Another problem is conflicting software like "C-Dilla". This license management and copy protection software is installed by, i.e., Need For Speed 4 and 3D Studio Max. At least NFS doesn´t tell you that. And if you uninstall C-Dilla, your license is revoked, 007
One possible solution is to get a program like "End It All 2" (i.e. from http://home.ptd.net/~don5408/toolbox/enditall/) that allows you to view and kill individual processes (even those you can´t kill with the task manager). Another (commercial) software for that purpose is the Norton process viewer, which even gives you the complete path to the files... probably the only really useful part of the Norton Systemworks suite aside from Ghost.