Relinking my previous answer from a similar question about the dissolution of Yugoslavia from a few months ago - I'm sure other members will have details to add as well.

The fall of Yugoslavia can be attributed to four main factors: The death of Tito, the fall of the USSR, the rise of nationalism, and (to a smaller degree) Turkish interests in the Balkans.

By the time WW2 ended, Josip Broz Tito managed to take control of Yugoslavia by becoming it's main war hero. Seeing how the Nazis had fuelled the fires of ethnic and nationalist extremism (see the Ustase) in the region, Tito's government sought to unify Yugoslavia through a national sentiment of 'Brotherhood and Unity', doing it's best to dismantle any ethnic nationalist sentiments within their borders, peacefully or otherwise. This, for the most part, worked pretty well while Tito was alive.

When Tito died in 1980, Brotherhood and Unity died with him. Since his cult of personality was what kept Yugoslavia unified, the government began struggling with rising ethnic nationalism. However, the both the Soviet Union and the United States still were providing Yugoslavia with foreign aid, and the former also intervened in more subtle ways to keep the country stable.

Considering how, at the time, the world was split in two, and the bipolar world order demanded stability within each bloc's main territories, the USSR couldn't turn a blind eye and let Yugoslavia fall apart, former rivalries between the two countries be damned. Of course, this didn't mean Soviet tanks would come in to crush rebellions like in Prague or Budapest. Things didn't get that bad in Yugoslavia until later.

When the USSR fell, so did this bipolar world order. Foreign aid ceased from both east and west, and the US became the sole great power in the world. That, for the Yugoslav government, meant their greatest ally to combat ethnic nationalism was gone. For the ethnic nationalists, however, it meant Yugoslavia no longer needed to abide their former Soviet overlords, and the opportunity to take over was at hand.

Serbia saw the rise of Milosevic in 1989, a Serbian nationalist, who slowly began placing his supporters in key government positions across Kosovo, Montenegro and Vojvodina. This led to a crisis in Kosovo, where Kosovar-Albanian miners went on strike, and Milosevic responded with force. This angered Slovenia and Croatia, and their press began demonising Serbia. Milosevic tried to censor the press, but it backfired. In order to resolve this, the Yugoslav government called for the 14th Congress, where representatives of all Yugoslav republics met to debate on what to do with the country, be it further the republics' autonomy, or go back to a Tito-style 'Brotherhood and Unity' system. Slovenia pushed for autonomy, but Milosevic and his supporters blocked all of their proposals. When the Slovenes leaved the congress prematurely, the Serbs wanted to continue without them. This made the other delegates angry, and they also left.

In 1990, Yugoslavia had it's first ever free elections, and the nationalist parties won in landslides. Independence referendums popped up left, right, and centre, and soon Yugoslavia was reduced to a mess of civil wars, ethnic cleansing, and a guy with a beret playing the accordion.

Lastly, I mentioned Turkish interests in the region. The Balkans have always been a geopolitically tense region, considering it's the main gateway between Europe and Asia, and yields control over the passage between the Mediterranean and Black seas. Even after the fall of the Ottoman Empire, Turkey still had (and has today) imperialistic ambitions over this territory, these days more oriented towards having political influence over the Islamic countries of the Balkans. This is the main reason why the Turkish government gave support to the muslim Bosniaks and Kosovar-Albanians.

In a speech given by Turkish Prime Minister Turgut Ozal in 1993, he claimed "Muslims of Bosnia and Herzegovina are for Turkey what Palestinians are for Arabs. To us, it is logical that Croats seek support in Croatia, Serbs in Serbia, and Muslims have no other choice but Turkey" (Translation from Turkish to Spanish, then to English). There's also the tensions between Turkey and Greece over the independence of Macedonia, but my sources are lacking on that particular conflict of interests.

Sources:

*Ruiz Guerra, N. "Cuatro Aspectos del Conflicto en la Ex-Yugoslavia".

*Ruiz Guerra, N. "La Desintegración de la Yugoslavia Socialista y los enfrentamientos Nacionalistas, Étnicos, y Religiosos en sus Ex-Republicas".

*Ruiz Guerra, N. "¿Por Qué Bosnia?"

*Peralta Diaz, M. "La Política de Turquía Hacia los Balcanes: ¿Un Esfuerzo por Recuperar Posiciones?"

*Ferrer Figueroa, C. "Occidente y el Desmembramiento de Yugoslavia".

*Ferrer Figueroa, C. "Bosnia-Herzegovina: ¿Hasta Cuando Un Solo Proyecto?"