When the computer screen of Andrew G. Eil '02 froze late last Sunday night, he figured the troublesome PC was just acting up the way it always does.

So he tried to reboot it.

Then he tried again.

And again.

The next day, Eil Visited the computer help desk in the Science Center basement and learned that his hard drive had been irreparably damaged.

And his was not the only one.

Eil's computer, like many others on the Harvard campus, was struck by the Chernobyl virus.

"They [the Science Center User Assistants] told me my hard drive was erased and that they couldn't see me until next Sunday," Eil said. "That doesn't help much."

The virus, which was triggered on April 26, disabled several hundreds of thousands, of computers all over the world. as computer experts had warned it would. At Harvard, it hit students with end-of-the-year projects looming especially hard.

Only about 2,000 computers in the U.S. were hit, probably because use of virus protection software is more prevalent here than in other parts of the world, according to Bill Pollak, a spokesperson for Carnegie Mellon's Computer Emergency Response Team (CERT). He said computer users could have downloaded a file with the virus in it unknowingly at any point in the last few months.

"It lies dormant in the computer system and then delivers its payload on the 26th of April," he said.

Pollak said that most reports of the virus came from home computer users or college students. He speculated that large corporations might have escaped major damage because they tend to use effective anti-virus programs.

This is the first outbreak of this devastating computer virus. While similar viruses can be triggered every month, Chernobyl was set for a particular day, this April 26, the thirteenth anniversary of the Chernobyl nuclear accident.

Not all students were struck. unaware--this week's issue of the Yard Bulletin warned first-year of the virus and told them to consult the Science Center help desk if they encountered problems.

Kunj Majmudar '99 said he heard about the virus last Thursday and backed up several of his files, just in case. Unfortunately, he was not worried enough to back up all of them.

"I made the mistake of not backing up my thesis," he said.

He came home from class Monday to find that the Chernobyl virus had struck--his thesis was gone.

Majmudar, whose these is due today, said he wasted an entire day dealing with the problem and scanning the single hard copy of his thesis into a working computer.

According to the CERT Welside the virus, which only affects computers running Windows 95 or 98, overwrites part of a computer's hard drive with random data. This leads the computer to think that the hard drive is empty, preventing a user from accessing the drive's files.

It is still unclear whether the virus, which is much more destructive than the recent Melissa virus, merely prevents access to the hard drive or irretrievably destroys the information contained on it, Pollak said.

Robert T. Dennis '02, whose computer froze early Monday morning while he was working on a paper for Expository Writing, said some of his Thayer entryway-mates told him there may be away to save his files.

As his roommate, entryway-mates, and pre-froshwatched, he tried to restart his computer and gotonly a blank screen with the message, "Disk BootFailure," he said.

Benjamin G. Delbanco '02, who lives in Dennis'entryway, worked with other students on thecomputer for several hours in attempts to recoverthe missing data.

Yesterday, he said, the group finally was ableto retrieve the information from Dennis' harddrive.

"We kind of jury-rigged it," he said.

Delbanco, who said he thinks his method couldbe applicable to other Chernobyl-struck computers,put the hard drive into a working computer anddownloaded the files in order to recover the datathat had been lost.

Though Dennis' hard drive itself will need tobe reformatted, Delbanco said he anticipates itwill soon be functional.

Meanwhile, the virus' unlucky victims are lefthoping for a quick fix and scrambling toreconstruct final papers as end-of-term deadlinesnear and the threat of late penalties looms largefor virus victims.

"If this were my fault in any way I'd be angryabout it, but as it is, there's nothing I can do,"Eil said.

"I'm trying to stay positive even though it'spretty much a total disaster," he added.

Rick Osterberg '96, coordinator of residentialcomputing, could not be reached for commentregarding the virus yesterday.

No one else could say for sure how many Harvardcomputers were struck by the virus or what thetotal amount of damage that it caused would be forHarvard's computer users