After you install Windows 7 on your computer, you cannot access the DVD drive, or you can only intermittently access the DVD drive.
This problem may occur if you use one of the following DVD drives on the computer:
Sony BC-5100S DVD
Sony BC-5600S DVD
TSST TS-L633B DVD+/-RW
To work around this problem, try the following methods in the order in which they are presented.
Method 1: Check for a firmware update
To check for an applicable firmware update, contact the manufacturor of the DVD drive.
Method 2: Disable the Adaptive Link Power Management (ALPM) feature
If you cannot find a firmware update, disable the Adaptive Link Power Management (ALPM) feature on the computer. To do this, follow these steps.
Note ALPM is a feature that puts a hardware device into sleep state after 100 ms of idle time. This is a power-saving feature. After you disable ALPM, you can still configure the drive to run in any one of three power plans: Performance, Balanced, and Power Saver. However, you cannot still benefit from the additional power saving that is provided by ALPM.
Click Start , click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
At the command prompt, type the following six commands in the order in which they are presented. Press ENTER after each command.