Alexander Ponosov, 40, the Russian headmaster accused of software piracy, was found guilty and fined 5,000 rubles (£97) by a Russian court.
Ponosov was charged last year after prosecutors found unlicensed copies of Microsoft software installed on his school's computers. The prosecutors accused Ponosov of causing Microsoft material damages of more than 250,000 rubles (about £195) - a charge that could have led to five years in prison.
The criminal case prompted reaction all over Russia, bringing support from well-know people including former president of the USSR Mikhail Gorbachev, who wrote a letter to Microsoft Chairman Bill Gates asking him to cancel his claims against Ponosov.
"A man who has devoted his life to teaching and bringing up children could be sentenced to imprisonment in one of the Siberian jails," Gorbachev wrote.
Russian president Vladimir Putin was asked by reporters to comment on the case.
"The law recognises the concept of someone who purchased the product in good faith. It is easy to just grab someone and punish them, but what we need to do is get to the bottom of each case, which is harder.
"If the legislation, which, as I see it, is not very adequate, needs to be amended, then we will reflect on this. But to grab someone for buying a computer somewhere and start threatening him with prison is complete nonsense, simply ridiculous," he said.
Ponosov did not admit guilt, saying he was unaware that the software on the PCs was counterfeit. Microsoft did not file any lawsuit against him.
During the first hearing the judge ruled to close the case on copyright violation and withdraw it from further hearings as "insignificant", but later both prosecutors and Ponosov - maintaining his innocence - appealed to the Perm Region Court requesting retrial.
After being found guilty this time, Ponosov said he disagreed with the court ruling and would file another appeal.