Attention: Do not open your computer or attempt any repair before reading the "Important safety information" in the Safety and Warranty Guide that was included with your computer for the computer. To obtain copies of the Safety and Warranty Guide, go to http://www.lenovo.com/support.

To replace the heat sink and fan assembly, do the following:

1. Remove the computer cover. See "Cover removal"
2. Remove the drive bay assembly. See "Accessing system board components and drives".
3. Remove the hard disk drive. See "Replacing the hard disk drive".
4. Disconnect the system fan cable from the system board. See "System board connectors".
5. Remove the two screws securing the system fan assembly.
6. Remove the system fan assembly by pulling the bracket outward and lifting it up from the system board to remove completely.

7. Install the new system fan assembly and install the two screws that secure the fan assembly.
8. Connect the system fan cable to the system fan connector on the system board.
9. Reinstall the hard disk drive. See "Replacing the hard disk drive".
10. Align the drive bay assembly with the two slots and rails on the sides of the chassis and slide the drive bay assembly towards the rear of the chassis until it snaps into position.
11. Reinstall the front bezel.
12. Go to "Completing the parts replacement".