iMac starts in safe mode only
Few days ago my computer suddenly refused to react to both mouse and keyboard. I had to force quit and restart again. Now it refuses to start normally: the progress bar goes up to half of its length and then it stops going on. So I can only start in safe mode. I have tried unsuccessfully following steps solar: (A) Disc Utility>S.O.S. (B) Apple Hardware Test i.e. power button whilst holding D key, but nothing happened: the screen remained blank (C) reset the System Management Control.
The EtreCheck Report says: iMac (2007)-Obsolete! Model iMac 7.1 1 2,4 GHz Intel Core 2 Duo (Duo) CPU 2-core 4 RAM-at maximum (I do not know how to post the Report here).
Can anyone say please if/what can be done to restore my iMac ? Thank you !