Uninstall that crappy Nero thing as fast as you can and install
http://www.imgburn.com/
Keep the settings at 'default' -( simply don't touch any setting)-.
Try again, at least you'll get a log when thing goes wrong.
If still problems:
Create some ISOs from valid CDs to test the reading capacities of your hardware.
Compare the ISOs to the CDs.
Next step:
Put a CD
RW in and try some things out.
At least you won't create a pile of frisbees when testing things out.
Keep the write speed a bit on the low side to begin, keep an eye on the soft and device buffer, keep the write speed so that they remain filled.
Uninstall any 'special cool looking non-essential' stuff *if* you have them.
Kill the useless widgets.
Close things that run on the background.
Always check the 'verify' box when writing.
As you have 4GB RAM try to set the buffer to 100-150MB.
[dit]
Also take a look in 'sheduled tasks' (admin tools) and deselect defrag if sheduled, heavy HD read/write on the background from this one and burning CDs is usually a bad combination.
If you're still using -*if*- Windefrag get yourself
http://www.auslogics.com/disk-defrag
and run it once in a while manually, disable any MS Defrag.