With a computer system crashing, high school students languishing in cafeterias and registrars pulling their hair out in the first few days of school, new Montgomery County Superintendent Jerry Weast fired the chief technology officer and took charge himself.

After two memos explaining in great detail the steps Weast was taking to bring a quick end to the serious problems in the new $4 million Student Information System, he fired off another. In a memo Monday, Weast said Ronald H. Walsh had been relieved of his duties, the first senior executive to be fired in recent memory, several school sources said.

The Student Information System, which keeps student registration, scheduling, attendance and academic records, was brought online recently.

After the system crashed last week, Weast secured promises of immediate help from the contractors, Marconi Systems Technologies Inc. and another firm, and persuaded about 100 people to work nearly round-the-clock to fix the computer problem and to enroll and register a huge backlog of students for classes.

"I watched him work over the weekend; he plays major hardball," said Board of Education member Nancy J. King (Upcounty). "But that's what we really wanted to happen when we hired him."

Throughout the first week of school, many high school students who needed to change class schedules or hadn't enrolled were sent to cafeterias or other holding areas as registrars struggled with frozen computers, printer errors and processing times the speed of molasses. "It's been incredibly frustrating," one registrar said.

School spokesman Brian J. Porter said the system is not fixed yet, but "we're a lot further than we were last week."

Still, Walsh's firing came as a surprise, as did the computer problems. The unexpectedness of the computer problems was one big reason behind his dismissal, sources said. The problems, largely involving insufficient computer memory, processing speed and disk space, were not that difficult to fix, they said.

"He was the guy at the top, the system was crashing, and he didn't have the answers," said one school source of Walsh. Another said Walsh "just didn't seem to appreciate the magnitude of the problem."

Walsh was hired in January 1998, after working for the system as a Lockheed Martin contractor. Weast on Monday named Susan Marks as Walsh's acting replacement.