A big software company raised havoc in an otherwise sleepy market this morning.

Long Island, N.Y.-based

Computer Associates

fell more than 15% by mid-morning after warning of weak sales in Europe. A Big Board stock, the software giant dragged the tech-heavy

Nasdaq

down with it, while the

Dow

and the

S&P 500

hovered slightly above their open. Meanwhile, analysts staked their bets on both sides.

Morgan Stanley

and

Smith Barney

downgraded Computer Associates, while

Cowen & Co.

,

UBS Securities

and reportedly

Goldman, Sachs

stayed loyal.

*****

What to do when an company with a history of checkered management loses three vice presidents in a day? Buy. At least that's what investors were doing in response to the seemingly bleak news from

Arakis Energy

, whose stock was up to 3 3/8 from its 2 13/16 open on Friday. As reported in

The Street

last week,

State Street Research

mutual fund manager Daniel Rice, whose natural resources fund is in the running as the number-one equity performer this year, has been buying Arakis big lately.

*****

Finally, Uncle Sam's largesse boosted a disaster play.

Invision Technologies

, which landed a $52 million contract from the Federal Aviation Administration to deliver explosive detection systems for scanning baggage at the nation's busiest airports, jumped over 30%, or 8 1/4, to 33 3/4 on the news.

Competitors' stock, however, did not respond much:

Magal Security Systems

was unchanged at 5,

Thermedics

fell 1/4 to 18 3/4 while

American Science & Engineering

gained 7/8 to 11 5/8. This summer all four stocks skyrocketed after the crash of a TWA plane that many suspected had been brought down by an explosive device. Since then they have all dropped precipitously and, excepting Invision, trade near 52-week lows.

By Jamie Heller and Avi Stieglitz