Since when and why did vampires become so popular (movies, books, TV...)?

Vampires have been prevalent throughout history. The idea of a creature living off the blood of humans with supernatural powers is found in many cultures so it is not surprising that we see them in modern literature. The lore of the vampire as we know it can be traced to Eastern European legend and to Irish author Bram Stoker. Stoker's novel Dracula provides the basis for most of what we would term an archtypical vampire. Stoker's fictional Count dracula was based on Wallachian prince Vlad Tepes who was actually called "Dracula". The term means son of the dragon and was given because his father was called "Dracul" after being accepted into the Order of the Dragon, a Wallachian military order. Vlad was scary enough on his own without supernatural aid. He was known as "Vlad the Impaler" from his method of dispatching his enemies. But, back to the question at hand.

Today's popularity of the vampire in literature and cinema stems from Universal's 1931 production of Dracula which was loosely based on Stoker's novel. Universal wanted to follow the novel exactly but with the Great Depression in full swing could not justify the expense and so based the movie on a stage play of the same name and cast Bela Lugosi as Count Dracula. The rest is, as they say, history