Go to the HP website HP.COM and do a search on the model number of your HP notebook and enter the model number in the box in the upper right conder and do a search. Select product manuals. Select disk drives and memory modules. Follow the instructions carefully. Th disk drives usually stored under a drive cover in the bottm of the notebook and the memory modules are stored under a cover on the bottom of your note book. Some HP notebooks have one memory module under the keyboard and another under the memory cover. You will have to get the same type of hard drive either SATA or PATA. If you get a new hard drive you will have to either copy the entire contents of you hard drive to the new one or you will have to re-install the operating systems and/or programs. You may not have recovery disks for the OS and installation source for you programs. If the notebook is not old you can get recovery disks for the notebook from HP.