I have submitted a couple of threads recently re this problem with no useful solution.
i was reformatting each time to get round it.
the answer is INCD seems to get corrupted from other program upgrades occasionaly, uninstalling INCD via the Control Panel in XP and re installing from the web or CD does not help if some versions of norton is loaded.
the solution is to use the clean INCD tool on the Ahead web site then reinstall from the web, this saves the problem of reformating and reloading the whole system again and works peacefully with Norton.
thank you for all those that offered help on those earlier threads.
i am still having this problem and after searching through the microsoft forum it seems to be a common problem and no definitive answer is forthcoming. i have searched microsoft knowledge and tried all suggestions to no avail.
i did the above (thanks david h) and now at least my copy of nero is working correctly but my windows xp burning software is still goosed. if i try to open a window to drop files in i get that error message `d is not accessible :incorrect function`
at least i know its not my drive now so thats progress i suppose!