Fred Silverman is fat and 40 but still fabulous. He is also bored. This could be his last year as the wonder boy of television, the ABC Entertainment president whose programming genius helped turn an also-ran into the No. 1 network.

But now Silverman is talking as though he's had enough time at the top. "The life of a television executive is boring," he complained at an ABC 25th-anniversary party here. "Boring! Boring, with a capital B."

Maybe it's just boring because he's so comfortably ensconced at the pinnacle. He shakes his head no. "That's not it. It's just that I've been doing what I'm doing now for eight years (he was previously at CBS), and it just gets to be all a routine. I mean, I know that every year the affiliates meeting will be held in some tropical place, and at that meeting, some guy from some station is going to stand up and gripe about the network programs spilling over after 11 o'clock and screwing up his late news show.

"I just know it."

So what do you do when you're Fred Silverman and the world is your blintz? What can follow such an act? It's like stepping down from the position of pope. Silverman won't say exactly what he's thinking of doing. "Something completely different, I'd like to try something in public service."

Surely he doesn't want to be head of USIA - that old rumor. "No, because that would be too much like what I am doing now."

Certainly there will be offers. Certainly there have been. At a press conference earlier, rumors ran wild. Was Silverman going to take over Paramount? "No." Had NBC tried to recruit him to replace network president Herbert Schlosser, said to be on the way out?

"These things are starting to get out of hand," Silverman groaned. "Right now I'm having discussions with Fred Pierce (president of ABC Television). But nothing has been resolved. I've heard rumors of my going everywhere from NBC to Walt Disney, and I think it's just ridiculous. I'm at a crossroads in my life; it's an important enough decision to me to take the time to make the right decision. It will be made very, very shortly."

Silverman never uses a "very" when a "very, very" will do.

For all the money he helped make for ABC - and network president James E. Duffy says ABC is now the most lucrative advertising medium "in the world," formerly a CBS boast - Silverman reportedly doesn't make record amounts himself: $25,000 a year, plus stock options and incentives. But Silverman seems interested not so much in money as in creative power, in the power to move "Fish" and double its ratings, in the challenge of running something huge and making it succeed.

In person he is so unassuming in appearance as to be almost invisible. No live wire he. Silverman has the same ineffecutal glaze and sloping plaintive eyebrows as in the standard corporate photos of him that ABC issues each year - where he always looks like maybe he's humming "Sewanee River." Yet when conversing even casually he looks at you penetratingly, as though flipping through a mental dossier that includes your 6th-grade report card and last year's tax return.

He made the cover of Time magazine last year, and Time scraped the walls at ABC in search of Silverman anecdotes. They proved hard to come by, for Silverman is not an unusually colorful, kooky or quixotic figure - in fact, he personified the very medium with which he is consumed night and day.

Visitors to his New York office may find themselves plopped into a chair and asked to look at a video tape of Marie Osmond's new hairdo, about which Silverman can wax rhapsodic at the drop of a hat. As you watch the TV screen, Silverman may be watching you; to him the whole world is a test audience.

He is one TV executive who actually and openly watches TV. He loves it and he wants you to love it. "He has the most contagious enthusiasm of any executive at that level I have ever seen," says one ABC staff member. That enthusiasm has a strong missionary streak; he wants everyone to share it and thinks nothing of calling underlings at 4 o'clock in the morning to talk things over.

Silverman got the idea for scheduling "Roots" eight nights in a row while watching it on videotape in his Manhattan home with his wife, Cathy, one weekend. They watched five hours one day and seven the next, Silverman says: "We just couldn't wait to see what would happen next." At CBS, this kind of boyish zeal was frowned on, and considered unsophisticated. How wrong can you get?Silverman is the true sophisticate; he is the man who doesn't give a hook about whether he appears sophisticated.

But he has a charmingly thin skin when it comes to remarks about himself. For at least three years he held a quiet grudge against a highly respected TV columnist who wrote that he wore "rumpled suits." These suits are no longer rumpled. Television is fattening, however, and Silverman now has a girth somewhat like the Little King in the comic strip.

Silverman is touchy, too, about attacks on the programs that all American watches. It seems genuinely to irk him that his shows have won tremendous popularity but almost no critical success. He actually thinks "Laverne and Shirley" is as good a comedy as "I Love Lucy" was. He's wrong, but he is entitled to his opinion.

"My personal feelings about a handful of TV critics, is that they have a very, very elitist point of view," Silverman says. "Anything that smacks of being popular entertainment is just written off as junk and trash and teeny bopper, and is stamped as being inferior.

"I personally believe that 'Laverene and Shirley' is an excellent comedy show, and everytime I pick up a paper and see somebody refer to it as trash or junk or this or that, I will take exception to that. I also resent having people take a program like a 'Happy Days' and compare it to 'The Mary Tyler Moore Show,' because each of these programs in my judgement is in its own way an excellent comedy show, each designed for a different audience."

Yet there are those who think that Silverman programs for one audience only and that audience consists of adolescents, sub-adolescents and arrested adolescents. NBC's Pual Klein calls Silverman' programming "kid porn".

"We are often criticized, and in some cases with some justification, for programming to teeny-hopper audiences and having cartoon programming," Silverman concedes. "We don't want to be known as the network that programs cartoons." Silverman claims that ABC's safe lead position will enable him to program shows that will "drive the level of quality up" with offerings such as the forthcoming "Harvey Korman Show."

Silverman also revealed that ABC will not rerun episodes of the controversial "Soap" series this summer, which means that even though ABC insists the show is a hit, it will be a costly one for the network. And may very well not be renewed for the fall season.

But to actor hugh O'Brian, one of many imported mid-range luminaries at the party, Silverman declared, "'How the West Was Won' is going to bring back the Western in three weeks." The series premieres on ABC Sunday, Feb. 12.

Asked if he will appear on the network's 25th anniversary show Feb. 5, Silverman said he'd be seen only briefly if at all during the finale, in which a huge cast of celebrities - everybody from John Wayne to the Fonz - sings, to the tune of the "Rocky" theme, "Ay - Bee - Ceeee, Flying High . . ." over and over again. It's like a revival meeting for the chosen people.

Silverman was irritated that the first excerpt from the show to be screened for the press here was a montage of cop and detective programs, replete with machine-gun fire and exploding roadsters. This could only help reinforce ABC's image as the network of guns, goons and girlies. Silverman said he would demand that the cop segment be shown late in the program, but he also expressed a wistful nostalgia for the violent "Untouchables" series and said he wished he could do that one today. Anti violence groups would scream bloody murder, however.

The clips from the past were reminders that ABC has always been the junkiest network. But today, the three networks seem almost neck-and-neck in that competition, and Silverman has given ABC a status it never had before and the dignity that goes with being the champion.

Higher up ABC executives and some network spokesmen try to down-play Silverman's role in changing the network's fortune, perhaps because they suspect he will be leaving soon. Silverman did not initiate the project that became "Roots," they'll say. But it was his inspiration to program it eight nights in a row and thereby help earn it ratings that broke all records.

Silverman didn't invent Fonzie either, but he saw what was exploitable in the character and was able to use that appeal to turn out other top rated shows. ABC's success is built on a firm foundation of pomade and leather jackets.

So they all love Freddy at ABC. They'd be pretty silly not to. The 25th-anniversary show opens with Barry Manilow singing, of the network's rise from 20,000 fathoms to celestial heights, "it's a miracle, a true blue spectacle, a miracle come true." And the miracle worker was sitting right there at Table 17, turning down a piece of cake and obviously wondering what his next miracle will be.