IMac will not get past chime & white screen

Question

iMac will not get past chime & white screen. I have tried all the start up key combinations I can think of (d or c etc) with a start up disc, but no joy. The disc drives seems ok - you can hear it working & it will eject OK.
Any other start up ideas, please?

Answer 1

Have you tried a safe boot? If not, hears how (it's straight from Mac Help):
To start up into Safe Mode (to "Safe Boot"), do this:
Be sure the computer is shut down.
Press the power button.
Immediately after you hear the startup tone, press and hold the Shift key.
Tip: The Shift key should be held as soon as possible after the startup tone but not before.
Release the Shift key when you see the gray Apple and progress indicator (looks like a spinning gear).
During the startup in Mac OS X 10.2 through 10.3.9, you will see "Safe Boot" on the Mac OS X startup screen.
During the startup in Mac OS X 10.4 or later, you will see "Safe Boot" on the login window, which appears even if you normally log in automatically.
To leave Safe Mode in any version of Mac OS X, restart the computer normally, without holding any keys during startup.
To learn more about Safe Boot check this page:
http://docs.info.apple.com/article.html?artnum=107392
Intel iMac (Early 2006)   Mac OS X (10.4.8)   2.0 Ghz, 1 MB