how can i install a second hard drive as a slave my master drive in 40 GB the slave is 120 GB can someone tell me how to Do That
Thank You jack

Yep. There are small jumpers on the hard drive itself; sometimes they are labeled or you can look at the drive specs to see which jumper setting to use.

Make sure the Primary hard drive has the jumper set to Primary. And the slave drive has to have the jumper set to Slave. Or you can set them both to Cable Select.

Now for the cable. Each IDE slot on the motherboard can have a cable with two attachments. I normally use the Primary slot for two hard drives, and the second slot for two CD drives.

The cables, once plugged in, have two plugs on them. The one on the end is the Primary, the one in the middle is the Slave.

Plug in the power supply to the new drive.

Restart the computer to Windows. The easiest way to prepare the new drive is to use software from the drive maker.

Then restart Windows and the new drive should appear as "D" (or whatever) in My Computer. The CD drives will be backed up a number, to "E" if it used to be "D" for instance.

That should be about it. Follow the instructions that came with the new drive regarding static electricity. And refer the drive maker's website if you have more questions.

Best Luck,
Bob

p.s. 120GB is a ~huge~ drive. You might consider using Ranish or another program to divide that monster space into smaller partitions.

A small tip:
You may want to connect a second hard disk to the Secondary IDE slot, leaving your first disk, and maybe a CD-ROM, on the Primary IDE slot. This allows ported and buffered operations between the disks to run much smoother, as the disks and IDE Slots can both be read from and written to near-simultaneously. The actual performance increase might be limited to factors such as the mobo chipset, drive type/manufacturer, and the OS you are running.
CD/DVD-ROM drives can be hooked up to the second (slave) connector for each IDE slot, with your favoured (or only) CD/DVD-ROM drive on the alternate IDE Slot to your favoured hard disk.