IBM ThinkPad 755CX Manual page 165

5
Insert the replacement drive. Press on the shaded area
as shown until the drive snaps into the connector;
then close the keyboard.
6
Connect the AC Adapter to the computer; then turn on
the computer.
You have completed the replacement of the hard disk drive. To
install your operating system and other necessary software, see
"What You Need for Your Computer" on page 174.
Replacing the Hard Disk Drive
Chapter 6. Installing and Removing Options
149