What's in a name? If the name is Stephen King, and it happens to appear before the title of your latest film (as in Stephen King's Sleepwalkers), that may be all it takes to guarantee a big first-weekend gross-even if the film itself received a C+ from audiences polled by CinemaScore. Following the recent Lawnmower Man, which has grossed nearly $30 million, Sleepwalkers is the latest King thriller to make a quick killing. And what of The Player, the most acclaimed American movie of the year, but one some have deemed too ''inside'' to become a hit? In its opening weekend, Robert Altman's Hollywood satire did superb business on 23 screens. But until it goes wider, which should happen in the next few weeks, there's no telling how The Player will play in Peoria. WEEKEND GROSS WEEKS IN GROSS* TOP TEN TO DATE RELEASE

1 $10.01 SLEEPWALKERS $10.01 1 Columbia (1,864 screens) 2 $7.85 BASIC INSTINCT $60.10 4 TriStar (1,825 screens) 3 $7.36 WHITE MEN CAN'T JUMP $39.21 3 20th Century Fox (1,929 screens) 4 $6.10 BEETHOVEN $15.50 2 + Universal (1,702 screens) 5 $3.55 FERNGULLY $3.55 1 20th Century Fox (1,400 screens) 6 $3.54 STRAIGHT TALK $9.47 2 Hollywood (1,477 screens) 7 $3.44 WAYNE'S WORLD $98.01 9 Paramount (1,715 screens) 8 $3.32 THUNDERHEART $9.16 2 TriStar (1,090 screens) 9 $3.13 THE CUTTING EDGE $13.10 3 MGM/Pathe (1,113 screens) 10 $3.01 MY COUSIN VINNY $34.94 5 20th Century Fox (1,329 screens) Audience polling information provided by CinemaScore *weekend of April 10-12 (all dollar figures in millions)