Thanks for the replies.
Have tried booting from the install CD but no luck. It won't boot up under any circumstances.
It may be nothing, but it seems strange that the front light is dim, almost goes out when the lid is three quarters shut then on full when the lid is fully closed. Or maybe it's nothing.
Will try to get some RAM to see if that makes a difference and maybe try a new hard drive. Any other thoughts would be welcome.
Thanks
Paul