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?