A federal court in Cleveland has enjoined computer manufacturer Hewlett- Packard Co. from committing certain unfair business practices against a small computer-maintenance firm - HyPoint Technology, of Cleveland.

The decision is the first victory for a computer-maintenance company, legal sources say.It is likely to have a broad impact on the multibillion-dollar computer- maintenance industry currently riddled with similar lawsuits against computer manufacturers.

HyPoint maintains Hewlett-Packard minicomputers at prices at least 20 percent below those of Hewlett-Packard.

In order to stop this competition, Hewlett-Packard stopped providing certain essential services to HyPoint on Aug. 1, 1987, Hypoint said.

HyPoint sued Hewlett-Packard last September in federal court in Cleveland, alleging that Hewlett-Packard was attempting to monopolize maintenance of its computers by cutting out competitors like HyPoint.

HyPoint argued it would go out of the business of maintaining Hewlett- Packar d computers if the court did not stop Hewlett-Packard's Aug. 1, 1987, policy change immediately.

HyPoint asked the court for a preliminary injunction.

Such an injunction is in effect during the course of the litigation, which normally takes several years.

The case now moves into the so-called discovery stage, in which the parties can obtain production of documents and testimony from each other.