What would have happened if the Romanov dynasty survived?

They'd probably have been exiled, forced to live abroad (in say Paris or London). They would have been ripe targets for assassination, so some might have been killed later on anyway. Eventually, the USSR would collapse (I can't see the Whites winning just because the Romanovs are alive) and the survivors/descendents might be able to move back to Russia, but they would remain out of power (like the Bourbons, Bonapartes, Hohenzollerns, and other defunct royal families across Europe).

Not for long. The trend of democratic governments replacing monarchical absolutism had already begun in Europe. Either the Romanovs would have adjusted themselves to democracy or would have been forced out by the people who were becoming more politically conscious..

As the others have said they would have fled into exile.

They would have been followed with a huge aristocrats and Royalist Russians, but what would have happened from then and the future would be speculation.

As most of Europe was at war also, it isn't likely they would be able to mount an offensive against the Communists to take much lands

Chetak

The Romanov's weren't "absolutely beautiful". This isn't a valid discussio of their fitness to rule.

Nicholas II was incompetent,and his heir was a haemophiliac unlikely to survive long into adulthood.

Had the dynasty survived as rulers of Russia,the country would have gone the same way as the Ottoman empire,becoming weaker and weaker as the years passed before collapsing and being deposed.

They wouldn't have come to London. They had already been refused asylum in England by George V.

I don't think that they would have survived Hitler. They didn't survive Lennon.