HP TC4400 - Manual (Page 112)

Removal and Replacement Procedures
Maintenance and Service Guide 5–29
6. Use a flat-bladed screwdriver to turn the processor locking
screw one-half turn counterclockwise 1 until you hear a
click.
7. Lift the processor straight up and remove it 2.
✎
The gold triangle 3 on the processor should be aligned with
the triangle icon 4 on the processor socket when you install the
processor.
Removing the Processor
Reverse the above procedure to install the processor.