A new hard drive is a popular PC upgrade, and it's no wonder with all those MP3s, home videos, and applications eating up disk space. These days, hard drives are available in sizes up to 100GB, and competitive prices make adding a new drive one of the easiest and most efficient ways to breathe new life into an aging desktop.
 

• Select a new hard drive. Unless you really need to replace a poorly performing drive, it's easier to add a second drive. When choosing a new hard drive, look for both capacity--get the biggest one you can afford--and performance. Generally speaking, a hard drive with a faster rotation speed will perform better. You'll also need to make sure that the drive you choose fits an open drive bay; hard drives come in 3.5-inch and 5.25-inch sizes. Finally, make sure you have any extras such as mounting rails and a ribbon cable that supports two drives.
   

• Prep your system. Back up your hard drive to removable media. If you use Windows 95 or Windows 98, make a bootable floppy disk using the Startup Disk tab in the Add/Remove Programs dialog box (Control Panel). From the tab, click Create Disk and follow the instructions. Finally, go to the CMOS screen and write down all the information on the BIOS settings for your current hard drive.
   

• Install the drive. Turn off your PC, open the case, and ground yourself. Slide the new drive into the bay or onto the mounting brackets. Then screw the drive firmly into place.
   

• Make the connections. The ribbon cable runs from your controller to your hard drive. If there is no free connector on the cable, you have to buy a new one. Connect the ribbon cable connector to the 40-pin slot on the hard drive. The ribbon cable has a stripe on one side of it, indicating which side of the cable plugs into pin one (located closest to the power supply connector) on the hard drive. The power-supply cable has a connector on the end of it--usually four sockets encased in a small sheath of white plastic. Plug that into the connector on your hard drive.
   

• Configure the drive. If you keep your existing hard drive (master), you'll set the new one to be slave by setting the jumpers on the back of the hard drive according to the documentation. Because your new hard drive is faster and bigger than your old hard drive, you can also switch between the two by changing the jumper settings. Finally, change the CMOS settings and format the drive so that your computer will recognize it.