This means you have not formatted the hard drive and/or you have not installed a workable Mac OS on it, or perhaps the drive is jumpered incorrectly. It should be set to Master.
Boot from the OS CD that came with the iMac. (Insert the OS CD. Reboot. Hold the C key down throughout the boot procedure untill the installer screen appears, may take several minutes.
You haven't provided enough detail for us to help you very much. Please describe in detail the steps you have taken so far, and the exact model and speed of Mac you have.
Please don't start multiple threads. You may want to review the forum rules. Excessive use of smilies is also not likely to help.