Grey screen,computer unable to read leopard disc, tried to reset pram using command option p and r with no result, difficulty ejecting leopard disc, sometimes able to get blue screen with holding down the c key, yet unable to perform first aid check, results are "unable to locate disc" when leopard has already been installed

You seem to be saying that if you put your Leopard installation disc (I assume CD or DVD) which is a boot disc, in the drive and boot the machine while holding down the C key, the machine boots so that the disc menu comes up (takes much longer since it is booting from a disc and not the hard drive) And, when you go to disk utility (or disk first aid) on the installation disk, and click on it, it does not find your hard drive, even when you go up to the menu and tell it to scan for discs. If this is the case, you definitely have some kind of hard disk problem. Resetting the pram will not fix that. The fact that the first aid program is not finding the hard drive at all seems to indicate that either something has physically gone wrong with your drive, or that the hard drive programming has been seriously altered. Did this happen as a result of your trying to install Leopard? Or did it just suddenly happen without anything else happening beforehand? You seem to be saying that if you put your Leopard installation disc (I assume CD or DVD) which is a boot disc, in the drive and boot the machine while holding down the C key, the machine boots so that the disc menu comes up (takes much longer since it is booting from a disc and not the hard drive) And, when you go to disk utility (or disk first aid) on the installation disk, and click on it, it does not find your hard drive, even when you go up to the menu and tell it to scan for discs. If this is the case, you definitely have some kind of hard disk problem. Resetting the pram will not fix that. The fact that the first aid program is not finding the hard drive at all seems to indicate that either something has physically gone wrong with your drive, or that the hard drive programming has been seriously altered. Did this happen as a result of your trying to install Leopard? Or did it just suddenly happen without anything else happening beforehand?

Have you gone to System and adjusted the screen their with the monitor and with appearance?. Are you able to accesses files? You may need to do a reinstall with your disc. Turn off computer, restart and hold down C key. You will then be taken to the disc but what you do not want is to earase the full disc you will want them saved, which will show up HD folder under previous system after installation and reboot. Have you gone to System and adjusted the screen their with the monitor and with appearance?. Are you able to accesses files? You may need to do a reinstall with your disc. Turn off computer, restart and hold down C key. You will then be taken to the disc but what you do not want is to earase the full disc you will want them saved, which will show up HD folder under previous system after installation and reboot.