try restoring it to before you installed nero. See if you get the error with anything else.
Look on the web for Memtest and dowload it. Use it to test your memory over night.
Also look for Prime95, will check to see if your computer is stable.
If you have two lots of ram, try using just one. Put them in different slots.
ALso go to Administrative tools and go to the Event viewer. See what it says there. See if there are any red crosses at the times where you have had the BSOD. use the web to find out what your error code means.
If all else fails, try reinstalling XP, (only take you 30 mins) and after installing basic graphics drivers, and direct X. install Nero, see if it works before you put other stuff on you system.
Also go into Control panel - System - Advanced tab - Hardware tab - device manager
Go through each piece of hardware, right click it and bring up the properties. See if any have any IRQ conflicts.
Also do you have APIC enabled in your bios. This will give you over 20 IRQ's to play with instead of the standard 15? .