Williams at Studio 54 in 1979. This photo was just on the auction block.

In the below video, the late and beloved Stewart Klein of Channel 5 talks about "America's hottest young star" in 1977. By the time this broadcast aired, Robin Williams was skyrocketing to superstardom (as Klein notes, he was "an unknown just six months ago") and pulling in $15,000 per episode on Mork & Mindy; he had also just signed to star in Popeye, and would soon release his first comedy album, Reality...What a Concept. Williams was also alienating the media at every turn, and in his broadcast, Klein delivers a few anecdotes to illustrate that:

"Williams opened at the Copa last night, photographers were barred. And he has turned down all requests for interviews, photos, and filming of his act. And at 4 a.m. this morning, Williams was cause of a brawl at Studio 54. After two members from a tv crew taped some shots of Williams at the disco, a fight broke out and the two newsmen were arrested along with Studio 54 owner Steve Rubell and one of his bouncers. All four were charged with harassment and criminal mischief."

Around this time, Robins was drinking and had a cocaine addiction, which he would eventually seek treatment for.

Here's another gem from 1977, featuring Williams in a telephone commercial:

And on the Richard Pryor Show: