Nowadays president of Ukraine is a criminal, who's been to jail twice. He grew up in a reaaaaaally bad neighborhood and had his own gang. During his presidentship the corruption grew up enormousley, destroying the economy. Of course corruption was support with implementing more "dictatorship" environment - Mass Media censorship, corrupted judges, increasing a number of police. Later there were elections, where his Party of Regions actually lost it, but due to mass machinations the majority in the parliament was formed by them. Since Kiev hated him and his party they didn't even allow to provide the elections of the mayor! Such policy throughout the whole time made people angry. And in the end it all burst out in mass protests with demand of president's retirement. But the problem is, that after all corruption scandals, and the amounts of time he violated the law he simply cannot go to retirement, because he will be arrested immediately.
That's why his only hope is to destroy the protests... phisically, so that no one would be brave enough to protest (same like in Russia and Belorus). He thought they will end up after his ignoring them, but he was wrong. But the problem is that a lot of poor (lumpen, ochlos) people in the country are easilly manipulated via propaganda and they beleive that it's not a protest against the government, but an attempt of Opposition to come to power (which is partly true). It's not a civil war, it's a battle between people who want to change the government & the system and corrupted policemen. The other side of people do not support protests due to missinformation and naiveness. But they will not fight against them with firearms. That's why it's not a civil war.
The protests were peaceful, but during this time people got arrested for nothing throughout the whole country. Also people simply knew that this man will not go away by himself, but only after showing force. That's why a lot of people didn't support peaceful protests and after 2 months of ineffectiveness it went in a radical scenario as more effective. Of course, as radical as they were, they weren't so dengerous, but police has taken firearms and real granades. How can you shoot in an unarmed man?? But police does this. So it's up to people wether to die under rain of bullets, or get your own...
Also, russian president Vladimir Putin is very nervous. If mass protests win in Ukraine, they might "infect" Russia. Despite the fact, that chances of 'infection' is very low, he demands from Yanukovich to crackdown the protest. That's why Putin supports Yanukovich financially and... with ammunition, millitary and FSB (former KGB) advisers.