More than 80,000 computer professionals and industry exhibitors arrived here today for the opening of a four-day National Computer Conference, the largest ever held.

But a weekend meeting of 32 computer business people, representing 17 independent computer service organizations, may have a larger impact on the booming industry.

In a meeting near O'Hare International Airport, to which at least one of the 23 participants brought along his handgun as protection, the local computer dealers recounted to each other alleged instances of threats, recriminations and theft of property.

The source of these alleged abuses, according to the businessmen, was Data General Corp., a Massachusetts computer manufacturer with sales of more than $500 million. Those present had all had business relationships with Data General at one time or another.

Bob Hahn of Grafton, Wis., who organized the weekend gathering placed an advertisement in today's Mid-western edition of the Wall Street Journal with a provocative headline: "Inducement. Lies. Fraud." The ad stated "If you've purchased or sold Date General Computers in the last five years and know the meaning of these words, I'd like to talk to you."

Data General spokesman Brad Stroup called Hahn's allegations "groundless." He said that reporters were being "sandbagged" by Hahn, who he said was being sued by "ex-employees and suppliers for not paying bills."

Hahn, in a phone interview, denied the allegations, adding that he had sued one former employee for "selling our information to Data General."

While the immediate cause of the meeting was the allegation of common problems with Data General, one dealer emphasized that the computer industry as a whole must face up to a broader problem.

Hahn has been battling with Data General for several years and currently is involved in 10 separate court cases involving allegedly former or current Data General employees as well as the firm itself.