You dont install a hard drive.
??? Hard drives don't come integrated on motherboards, so they must be installed:cyclopes:
To answer the original question:
It is fairly easy to install a new HDD.
1) Find out what your motherboard supports (IDE, SATA or both). If both, get SATA.
2) Pick HDD according to what brand, size, speed, and interface you want.
3) Turn off and unplug computer.
4) Open computer case.
5) Install HDD in case using appropriate sized screws.
6) Locate free Molex or SATA power cable and plug into HDD.
7) Locate port for hard drive (IDE or SATA) and plug appropriate HDD cable into port on HDD and on mobo.
8) Confirm all connections.
9) Close case
10) Plug in computer and turn on.
11) Hit DEL upon boot up to enter BIOS.
12) Ensure that new HDD is detected in BIOS.
13) Exit BIOS.
14) Load Windows
15) Open Disk Management and format drive.
16) Use hard drive:cyclopes: