In an attempt to stem a downward trend in prime time ratings, Nickelodeon will put greater emphasis on kids rather than the recycled sitcoms of Nick at Nite. The network will go after the kid demo left wanting by ABC's abandonment of Sabrina and Boy Meets World. Nick will add an hour of kid programming to Friday nights beginning this fall, running the block from 6 p.m. to 10 p.m. The 9 to 10 p.m. spot is currently populated by The Brady Bunch and The Beverly Hillbillies, part of the Nick at Nite lineup. Also in the fall, the Monday-Thursday Nick at Nite block will be bumped a half-hour earlier to 8:30 p.m. Nick suffered a 10% decline in rating and delivery in prime time in first quarter 2000 compared with last year, according to Nielsen Media Research data.