It's official. The marriage of the former Planning Research Corp. in McLean and Advanced Technology Inc. of Reston was made legal Jan. 1. The new name of the merged company is PRC Inc.

The company informally has been known as PRC since September.

The combination creates a company with 8,000 employees and $700 million in revenue. Advanced Technology's offices in Reston still are being used, but headquarters is officially in McLean now.

Advanced Technology lost its separate identity when Black & Decker Corp. inherited it and PRC as part of its acquisition of Emhart Corp. in April 1989.

The Towson, Md.-based manufacturer of power tools tried to sell both companies but changed its mind when the market for computer companies -- and just about any other kind of company -- fell apart last summer.

Instead, Black & Decker has decided to keep PRC in its portfolio, and expand the computer company's horizons from the government sector to commercial clients who need help with networking their computer systems.

"Everyone is used to it now," Scott Thompson, chairman of PRC, said in a recent interview, referring to the combination of the two companies.

Thompson was president of Advanced Technology before he was tapped by Black & Decker to head what was then PRC and ATI. "It's a good blend," he said.