Disgruntled fans, mystified by network scheduling, keep asking about their missing favorites. Two questions crop up most frequently: Where’s “Everwood”? Where’s “Commander in Chief”? “Everwood,” the WB drama that hasn’t offered a new episode since Dec. 8, returns at 8 Est tonight. In two fresh, back-to-back installments, fans learn the latest about the family life of Dr. Andy Brown (Treat Williams), the prescription-drug addiction of Dr. Jake Hartman (Scott Wolf) and the romantic turmoil between Ephram Brown (Gregory Smith) and Amy Abbott (Emily VanCamp). “Commander in Chief,” the ABC drama about the first female president of the United States, hasn’t presented a new episode since Jan. 24. It rejoins the lineup April 18. Geena Davis won a Golden Globe for playing President Mackenzie Allen, and “Commander in Chief” remains the most-watched new series from last fall, just ahead of CBS’ “Criminal Minds.” So how could “Commander in Chief” be in such deep trouble? Start with erratic scheduling, production problems and major shakeups behind the scenes. Series creator Rod Lurie left, and super producer Steven Bochco stepped in. Now Bochco (of “NYPD Blue”) is focusing on a fall pilot, and executive producer Dee Johnson is guiding “Commander in Chief” to the end of an 18-episode season. (That’s another sign of problems: Most series produce 22 episodes a season.) When ABC last week announced the season finale dates for “Grey’s Anatomy,” “Desperate Housewives” and “Lost,” the network was mum on what’s ahead for “Commander in Chief.” The presidential saga will have seven new episodes to air in the six weeks before the season ends May 24. Renewal in May depends on how “Everwood” and “Commander in Chief” perform in the season’s final weeks. The odds are better for “Everwood.” The WB is going out of business, but the new CW network will need established series to start next fall. “Everwood” did well on Thursdays last fall, and the drama will probably produce higher ratings after “7th Heaven” on Mondays this spring. “Commander in Chief,” however, did the unforgivable in today’s television world. It became a favorite among viewers older than the 18-to-49 age group, reducing its appeal among advertisers. ABC hurt the show with misguided nurturing. The network kept “Commander in Chief” off the air in February to protect it from Fox’s “American Idol” and the Winter Olympics on NBC. In March, in President Allen’s slot, ABC subbed “Sons ‘ Daughters,” a critical favorite that has yielded anemic ratings. Out of sight, “Commander in Chief” was out of most viewers’ minds. With President Allen off the schedule, CBS swooped into the same time slot in March and premiered “The Unit,” a military drama created by playwright David Mamet. “The Unit,” starring Dennis Haysbert, has emerged as the season’s most-watched new drama. Last season, “Desperate Housewives” and “Lost” were big fall arrivals that electrified the television industry. Nothing new this past fall generated a similar reaction. The major newcomers this season arrived at midseason. In addition to “The Unit,” CBS has another hit in “The New Adventures of Old Christine,” a comedy with Julia Louis-Dreyfus. The midseason has produced many failures – “Love Monkey,” “Emily’s Reasons Why Not,” “The Book of Daniel” – yet CBS single-handedly is proving that viewers still want new scripted programming. Reality has thrived at midseason. Two editions of Fox’s “American Idol” sit atop the ratings. “Dancing With the Stars” revived ABC’s fortunes on Thursdays and Fridays. “Deal or No Deal” is one bright spot on NBC’s schedule. In the early going, “American Inventor” has performed well on ABC. In this rapidly changing landscape, President Allen couldn’t compete. ABC wouldn’t let her. The network frittered away the biggest hit of the fall, and renewal seems highly unlikely. The probable legacies of “Commander in Chief”: Davis can polish her Golden Globe, and fans can mourn a series that might have been the next “West Wing.”