There were many factors that caused the Cold War be set in motion, however most of these factors can be generalised into a common mistrust between the two superpowers that had emerged at the end of World War II, the Soviet Union and the United States of America.
One of the main reasons was that there were huge differences in the way that the East and West were led and the disagreements about this point. The West was a democratic state, while the East was a one-party state. Theoretically the country is run by elected councils called Soviets. However most of the members are Communist so the Party basically controls the country. In the East there were strict limits on human rights whereas very few in the West. In the West average living standards were much higher than in the East. The reason for this in the West is because wealth is distributed unevenly, therefore there are more poor people.
In the East the wealth is distributed more evenly, making less people rich or poor as well having a government run economy i.e. profits go to the public whereas in the West the economy is free market meaning that profits go to the company.
Another main reason was that there was a long history of mistrust between the two countries starting off with the Russian revolution of October 1917 where the Royal family was murdered. The Communists, when they came to power, made drastic changes to the way that the country was run which angered the West, so much so that in 1918, when the Russians made peace with Germany, the West sent in armies to destroy the Communists. They failed and the Communists stayed in power.
Another reason was the fear of expansion by Russia, a potentially hostile...