Make sure you have an available connection to add a new drive. The IDE interface is used by hard drives, CD-ROM drives, DVD drives, tape backups and other devices. You can only have 4 devices connected to an Enhanced IDE interface. Your boot hard drive will be the master device on the primary channel. Purchase a new hard drive.
Hard drives continue to get bigger and faster while the price remains steady or drops.
Format the drive. My computer may have a virus. The basic steps to removing a virus is to power the infected system down, boot up from a clean diskette, then check the system for a virus. Power your system off. Don't just hit reset but completely shut it down.