It's probably an virus infection. Scan your PC online(If you are on unlimited plan), Otherwise use any good and updated AV to scan your system.
Monitor processes in task manager and also the startup entries from msconfig.
Did it started recently or the problem was there from the very first time??
Do you use internet?? If yes I would like to recommend an online scan(If you are on unlimited plan).
What PSU do you have, since you have upgraded other components and not upgraded the power supply, there may not be enough power to run the Dvd player.
If that was the problem, then try removing any extra HDD or VGA cards and try to copy from the disk again.
a normal 400W PSU is enough to run this rig. But not crappy 400W PSU's?? Which brand PSU are you using??