Students returning to California State University, Stanislaus, this month were greeted with an ultimatum: Update your computer's virus protection or lose your Internet connection.

The Turlock school isn't the only one taking steps to protect its computer system. Officials at University of the Pacific, Modesto Junior College and other campuses nationwide are working to prevent computers from spreading viruses.

"We were doing fine until last week," said Maithreyi Manoharan, associate vice president for information technology at Stanislaus State. "Once the students came back, we had major problems."

It is estimated that 80 percent of the computers in the on-campus dorms at Stanislaus State have been infected with a virus, said James Koelewyn, 23, a business major and member of the school's technical-support team.

"We get interruptions in the service through the entire campus every once in a while because of the dorms,"

Koelewyn said. "My phone has been ringing off the hook for two weeks now."

The viruses spread quickly because students who live on campus plugged their computers into the university's network. Many of those computers had the Sobig.F virus or Blaster worm.

A worm is a program that finds computers to infect over a network and is not spread through e-mail. A virus is spread through e-mail or files. Both clog up networks with large amounts of data and slow down connections to other computers or the Internet.

Ralph Iscoff, 18, a computer information systems major at Stanislaus State, said his computer got a virus after he arrived on campus, and the school cut his Internet connection.

"I had to clean it up and then called them to turn the connection back on," said Iscoff of Manteca. "The school was really quick about turning the connection back on."

Iscoffe said he's updated his virus software and added two firewalls. "I'm trying to be extra safe now," he said. "I don't want to lose my connection again."

Instructions to thwart infection

Students this week are getting fliers telling them to make sure their computer virus protection software and operating systems have been updated.

"We are putting together a CD with all the fixes and instructions on how to patch the computers, giving it to those with problems, and telling them they have to update it or else we will disconnect them," Manoharan said.

Students aren't the only ones being warned. She also unplugged a couple of teachers' infected computers until they were cleaned, she said.

The university also purchased a license to distribute McAffee's antivirus program and is giving it to students. So far, more than 200 CDs have been handed out, Koelewyn said.

Manoharan's staff plans to disconnect the dormitories from the university's network, putting the student housing on its own.

The new equipment for the dorms and the McAffee license cost $15,000, she said. "It was a lot of money, but well worth it."

At UOP in Stockton, 300 to 400 computers were infected when students returned.

"I got a variant of the Blaster called Nachi," said Thayer Merritt, a 19-year-old business student from Boring, Ore. "It only took 10 minutes of being connected to the network to get it."

He ran a free virus scanner downloaded off the McAffee Web site to clean his computer and then installed an antivirus program that UOP is giving students.

"We dealt with it like many other institutions did -- we fought it system by system," said Larry Frederick, the chief information officer at UOP. "We were luckier than others in that we only had to shut off the connection to one residence hall, and we did that briefly during the night.

"They probably didn't even notice it," he said.

Modesto Junior College had it a little easier than the two larger colleges because it doesn't have students living on campus, said Felicia Osnaya, MJC's interim technology manager.

But MJC students can download files infected with viruses in computer labs, she said.

Several months ago, Osnaya's team installed a program, Deep Freeze, that erases all new information -- including infected files -- added to a computer during the previous lab session.

She's also spending a lot of time educating computer users on how to avoid getting a virus.

"It isn't just students, but staff members also don't know how to update," said Linda Hoile, MJC's director of marketing and public relations. "I opened an e-mail from the president's assistant thinking it was a joke. Instead, it was the 'I Love You virus.'"

More drastic steps elsewhere

Some colleges in the United States are taking more drastic steps to protect their computer networks:

Oberlin College in Ohio is threatening to fine students $25 for inadvertently spreading a virus. Students there must have their computers checked for viruses when they arrive on campus. College officials said they found infections in nine out of every 10 which were running Windows software.

At the University of North Texas, technicians are removing viruses from roughly 16 computers every 90 minutes -- plus assessing a mandatory $30 cleaning fee.

Vanderbilt University found infections in computers of roughly one-fourth of its returning 5,000 students. Stunned technicians shut off connections to nearly 1,200 computers they determined were infected and gradually restored service over the next several days after ensuring each machine was clean.

Salisbury University in Maryland shut down its entire network for students in residence halls for one day, even after employees spent two weeks cleaning 500 school computers.

UOP's Frederick believes these incidents will change the way universities manage their networks and computers.

"This is sort of a wake up call for higher education that business as usual will not cut it anymore," he said.

"Had those viruses been more lethal, it would have been an entirely different experience."