Q: Can't eject disc from desktop iMac. Can only get as far as screen illuminating and keypad eject button has no effect although disc can be heard whirling round?

All of the start-up options I've tried end up with the the same result. A grey screen and after 35 seconds a flashing question mark.

I've tried a different approach and seem to have got further. I've found installation discs 1 and 2 that came with machine,10.5.x Leopard. it was upgraded to Snow Leopard later with disc purchased from Apple, three sets if I remember correctly.

1/ Insert 10.5.x and hold down C on start-up.  Grey screen appears with Apple logo and spinning gear wheel then blue screen and language option.

2/ Mac OSx Leopard installer. Keyboard and mouse operational.  Terms and condition - agree.

3/ Then 'Select a Destination' Where do you want to install Mac OSx?  Five icons displayed including 'Finder'. None of which respond to mouse click.

4/ Displayed across top of screen is 'Apple for Mac OS Installer' (version 1.0.3) with drop-downs      File     Edit     Utilities     Window.

5/ Selected 'Utilities'/  Grey screen with Apple logo and spinning gear wheel. Then blue screen.   

6/ Selected 'Verify Disc' (Only one of four highlighted).  Result was 'Error The underlying task reported failure on exit'. Install disc 1 is still in disc drive.

What would you advise that I do now?