I'd just press random buttons...... Not helpful by much.
The disc can't be loaded from in the OS properly.
Follow these steps: ==> 1. Take the disc you thought didn't work and put it in the top drive.
2. Instead of trying to use F8 or F12 and to have assumed something good happened that will make this work, try going into the CMOS by pressing either F2 or Delete. If these keys don't work use things like ESC, F9 or Ctrl+F11. When in the CMOS (it is probably a solid color in the background with lots of words and numbers) navigate using the arrow keys or any listed until you find something that says "Boot Order." Make sure booting from and CD/DVD drive is first, and that your hard drive is listed after the CD/DVD drive.
3. Now do whatever your CMOS asks to save and exit, restarting the computer. Upon restart it will say "press any key to boot from CD." (unless its forgeted brown townly with viruses) You will have five seconds to press a keyboard button to initiate the reformatting.