Moviegoers so hungry for red herrings that they don't mind sloppy service can pig out gleefully at "Happy Birthday to Me." The pickings look awfully lean for all other tastes.

"Happy Birthday to Me" is served up as a bloodthirsty tale of a psychopath on a murder spree at a posh private school. The none too sympathetic victims are confined to the members of a senior class clique known as The Top Ten. The obvious mystery revolves around the question of whether Melissa Sue Anderson, a bland misfit in the midst of such an insolent, thrill-crazy bunch, is going to be revealed as the ultimate victim or the ultimate schizo.

Anderson's character, Ginny, is unable to remember certain events connected with a murky tragedy that cost the life of her mother a few years earlier. Her wealthy father, Mr. Wainwright, played by Lawrence Dane, tried to console her with lines like "Ginny, Ginny, Ginny," but she's determined to break through the traumatic mist. "Daddy, I have to remember!" she cries. "David said unless I stop repressing those memories, I'll never be completely cured."

David is Dr. Farady, a painfully earnest shrink portrayed by Glenn Ford, who appears to be the Hollywood guest star in this Canadian taxshelter production. Although a comforting presence, Ford is disconcerting when he appears for his first consultation with shirt unbuttoned down to the solar plexus and a gold chain dangling from his neck. Maybe he rushed onto the scene still groggy from a flight from California. When Dr. Frady next appears, Ford has buttoned his shirt and acquired a necktie, probably closer to regulation in this eastern prep school setting.

Dr. Farady drops in and out of the confusion in ways that lead you to expect the company had Ford's services for only a limited period of time. After the recent wave of deranged shrinks, it's something of a relief to report that Dr. Farady is merely incompetent and unwary. Ford also speaks one of the funniest lines in the movie. Appearing with almost magical promptness after the solitary heroine screams, "David, help me!" Ford reassures her, "We're coming very close, Virginia. We've got to find the link between your trauma and your friends."

Although screenwriters John Saxton, Peter Jobin and Timothy Bond seem to imagine they've been devilishly clever about working out this threadbare puzzler, what they've actually done is call constant attention to their fakery. They clutter the continuity with bogus hints and mock threats between obligatory murder highlights, the nastiest being the obscenely gruesome stabbling illustrated in the ads -- a shish-kebab skewer rammed down somebody's throat.

"Happy Birthday to Me" is a cheesy tease from the outset. The opening sequence entraps the first victim, then allows her to escape, then entraps her again and allows her to escape again. By the time the filmmakers get around to making a murder scene stick, you're already fed up with their methodology and wondering why the movie wasn't called something like "The Coed With Nine Lives."

A similar approach governs the exploitation of the sleepy-lidded, innocuous Melissa Sue Anderson in her change-of-pace starring role. After seven years of cloying wholesomeness as Mary Ingalls in "The Little House on the Prairie" series, any teen-age actress would no doubt find the idea of an unwholesome thriller pretty tempting. Unfortunately, Anderson hasn't shaken off her somnambulistic personality by merely changing roles. Every so often I was alarmed that she was about to nod off in mid-take. I wanted Ford or someone else handy to grab her by the shoulders and shout," "Snap out of it, girl! There's a scene to be played!"