I have a penryn blackbook. Lately, my DVD drive won't calibrate the laser to burn DVD's and the drive consistently checks for new media even after the computer has been turned on. I have repaired permissions, yet the problem still exists. Are there any steps I can take to try to fix this on my own? If not, what are peoples' experiences with servicing their computer? My computer is perfect besides that and am nervous that repairing it will only causes more problems. Let me know what you think! Thanks!