You didnt by chance change out a 80 wire/40 pin cable for a 40 wire/40 pin IDE cable?
Plus go into your control Panel-System-Hardware-Device Manager-under your IDE controllers and make sure its running in UDMA mode.
Are there scratches on the CD onto which you are burning your data files? CRC error occurs(normally) when incomplete bits are present OR when there are scratches on the CD(when burning). Please look into this. Have you tried using another CD?
Also, I would like to know any changes made by you to Nero or the burning device.
It has happend to me try using windows built in cd burning if you are running windows xp or vista