Why did the provisional government [of Russia before Communism and Lenin gained control post-WW1 after the fall of the Tsar fail?

Why did the Provisional Government fail? One of the main reasons that Russia's provisional government failed and why the Bolsheviks were able to gain power is the First World War. The war was a disaster for Russia- people were already very discontent at the failure of the war and the shortages it caused- it was a major cause of the March revolution to overthrow the Tsar. The war was already going badly when the June-July …

…on a short term scale the ruthlessness and effectiveness of the Bolsheviks which disposed of the provisional government and brought about its downfall. Whilst various factors all contributed to the downfall of the provisional government, ultimately credit must go to the Bolsheviks as when most other even radical parties had joined with the provisional government, it was the Bolsheviks who seized the golden opportunity to take power masterfully making themselves the new leaders of Russia.