Athlon 64 4200dc, 2.0Gb DDR2, MSI Platinum (latest BIOS), XP Pro, Nero 6.1.1.6.

PC works perfectly for everything except copying CDs. As the PC is finishing a copy, the system shuts off instantly. It then cannot be switched back on until the power has been unplugged and replugged. It will copy DVDs. It will burn data compilations, anything except copy CDs.
We have swapped the memory, cpu and motherboard, but it still does it. Weve uninstalled and reinstalled Nero. Virus scanned (NOD32), spyware scanned etc etc. Help..............