The Department of Defense is facing an enemy as formidable in its own way as Saddam Hussein - multibillion-dollar computer systems that are so complex they threaten to immobilize weapons.

Computer-generated orders have become vital to the Pentagon's newest and "most advanced" weapons systems. Without computers, the weapons can't identify their targets and fire, and the aircraft and ships can't navigate.Some of the Pentagon's big-ticket items are being held hostage to their computers. According to two congressional investigations, the Army's Apache helicopter, the Air Force's B-1B and "Stealth" B-2 bombers, the Navy's Los Angeles-class attack submarines and the Trident II missile program all have suffered cost overruns and production delays because of the computer system they have in common - called embedded computer systems,

Bugs and design changes in the BUSY 1 and 2 and the ALQ-161 embedded computer systems have left some of the newest weapons of war brainless.

The B-1B squadron, for example, is sitting in hangars waiting for Air Force computer programmers to "work out the bugs" on the ALQ-161, a congressional source told us. Before the bombers can successfully complete a mission, the computers must be installed and tested. Meanwhile, the entire $8.3 billion wing is grounded.

Rep. John Conyers, D-Mich., and his staff have investigated problems with the embedded computer systems. "The real heart and guts of these systems don't work," one Conyers aide told us.

The Defense Department spends more than $30 billion a year to develop and manage computer systems for newfangled weapons. That's $21 billion a year more than the Pentagon was spending 10 years ago. But despite throwing billions of dollars at the problem, the Pentagon can't master the computers.

Government documents obtained by our reporter Paul Parkinson show, for example, that it takes more than 800 software programmers to input 3.2 million lines of instructions into the BUSY 2 so the Navy's latest super submarine, the Seawolf, can be launched.

The work is so complex and specialized on the BUSY 2 that the Pentagon contractor initially couldn't find enough qualified people to do it.

The Seawolf would be a bad idea even if its computer programs were as simple as Super Mario Brothers. As we reported last year, the Navy is hellbent on launching the first Seawolf at a cost of $2 billion to face down a threat that doesn't exist - war with the Soviet Union. The Seawolf is so expensive that even during the Cold War it would have been folly.

With too many weapons systems, there is disturbing evidence that the Pentagon is following a high-risk policy of "buy before you fly."

In the case of the Seawolf, the Navy is rushing headlong to develop BUSY 2 separate from the rest of the submarine. The Navy is betting your tax dollars that the BUSY 2 will be ready when the rest of the Seawolf is seaworthy.

The Navy is trying the same thing with its Los Angeles SSN-688 class of submarines. But problems with the BUSY 1 (the predecessor of BUSY 2) have already caused a 17-month delay and will cost taxpayers an extra $272 million. Congress should cut the purse strings on Pentagon computer development until the technicians can catch up with the equipment. Or at the very least, the Pentagon should insist that its computers will work with its weapons before billions of dollars are thrown down the drain.