then do a Safe Boot > Mac OS X: Starting up in Safe Mode
1. Be sure your Mac is shut down.
2. Press the power button.
3. Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
4. Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).
Now try Burning a CD or DVD......
If your using a wireless keyboard, try holding the keys down at the chime instead of before. Alternatlly you may want have to use a USB keyboard for entering resets and startup commands.