The Prince William County School Board has asked a federal judge to override the orders of a Virginia education official and allow it to expel a 14-year-old handicapped youth who allegedly has acknowledged selling drugs at school.

The board's decision in March to kick the youth out of school was reversed last month by an official in the State Department of Education who said the board could not expel the youth because his involvement with drug dealing was related to his handicapped condition.

The board filed suit this week in U.S. District Court in Alexandria against the youth and his parents, seeking reversal of that administrative order on the grounds that the youth's handicap had nothing to do with his alleged drug dealing.

According to the suit, the youth--a member of a learning disabled class--told his principal that he sold illegal drugs on three occasions on school property in January during the school day. The youth also signed a statement to that effect, the suit said.

After a school committee and learning disability coordinator held there was no relationship between the youth's condition and the drug sales, the school principal recommended the youth be expelled, the suit said.

The county School Board held a hearing on the recommendation in March, at which the youth allegedly again admitted his involvement with drug selling, the suit said. The board voted to expel the youth.

After the board's decision, the youth requested a hearing by the state official and was reinstated at school. The board said it filed the suit because it had exhausted administrative steps that could overturn the state official's ruling.

School Board Chairman Gerard P. Cleary declined to comment yesterday on the suit. The youth's parents could not be reached.