He was a comic genius who had only one speed - full throttle. From the moment he burst into our lives as an alien on Happy Days, he amazed us with a range of talent that left us breathless. Yet, behind the manic shtick of Robin Williams was a man who was deeply plagued by depression. He had other demons, such as alcohol and cocaine. Still he kept us entertained to the very end, which made it all the more unfathomable to his legion of fans and admirers when he took his life, at the age of 63.