You can purchase a new hard disk drive(hdd) from an authorized reseller or from IBM/Lenovo.
Take precautions when handling a hdd. Don’t apply pressure to the cover of the drive.
– Turn off the computer and disconnect all cables.
– Close the display and lay the Thinkpad face down so the battery is away from you.
– Remove the battery as a precaution.
– Remove the screw on the near left side of the Thinkpad that holds a cover to the hdd compartment.
– You’ll have to open the display cover slightly to detach the cover from the hdd compartment.
– Pull the cover and the attached hdd out of the Thinkpad.
– Detach the cover from the hdd and install it on the new replacement hdd.
– Insert new hdd and cover into Thinkpad and make sure it is seated firmly.
– Reinstall the screw and battery.