Which version (if any) of the nVidia nForce chipset drivers do you have installed? You say the burner has never worked... is this a brand new build?
I've had nothing but problems myself with the nForce UDP (Asus A7N8X Deluxe) and attempting to update it with a new release has fubar'd my CD burning (and everything else in the process) twice now. I was able to fix my CD burning issues by avoiding the nVidia IDE drivers and sticking with the default WinXP IDE drivers.
Check out
nForcersHQ for lots of info on this and similar issues with nForce boards. You may want to update the drives firmware if you haven't already:
Lite-On Firmware (latest version is QS0C)
Good Luck
Edit: Forgot to mention - since you're using Nero on WinXP, avoid installing Adaptecs ASPI layer as it's unnecessary and can cause conflicts (did on my system anyways).