omg i have always loved the vampire topic!!
so ancient vampires were beasts, they looked hideous with animal like looks. they cant survive in the sun and have a fear or holy water. apparently vampires were started because of a disease in the 1800s. but now like every other living thing on earth, current vampires have been evovled into more human like. living amongst humans without ppl noticing

- What can make vampires die?
a wooden stake through the heart
silver, cross (preferably silver cross) and holy water also affects them by burning the contact surface
in some stories garlic also hurts vampire not to the point of killing though
usually after killing a vampire, its body is set on fire to make sure it doesnt come back

- How do humans turned into vampires?
usually if a vampire bites a human, then the human drinks some vampire blood

- Do vampires look like humans?
yes, but they are pale (very white skin), they have a weird eye color and their skin is cold

- Can vampires sleep at night?
no they dont sleep

- If we use guns to shoot vampires, will they die?
only when you use silver bullets

- Can vampires survive under spotlight?
yes they do, but they burn when they are under the sunlight. the slightest sun ray can kill a vampire i.e. the vampire will burn

I'm pretty sure you can spin it whatever way you like - there are many myths and legends :)
Twilight wouldn't be helpful, though

- What can make vampires die?
a wooden stake through his/her heart

- How do humans turned into vampires?
the vampire bites that person and inject vampire blood into that person blood

- Do vampires look like humans?
well yeah? i think so? O_O

- Can vampires sleep at night?
i don't think they need sleep at all... =_="

- If we use guns to shoot vampires, will they die?
um nupz.. unless it's a gun with special bullets...

- Can vampires survive under spotlight?
spotlight yes.. sunlight will just weaken them but in some case can burn them also...

hope it helped.. ^^;

i know a little about vampire,
and, i read somewhere that vampires are immortal which mean they don't die,
humans turn into vampires when vampires bite that human and onto that person's blood,
vampires look like humans but they slightly look different in which they look much more paler than human which korean called, "mixed blood" and their hands or bodies or skins are much more colder than normal human because they have cold blood instead of warm blood like us,
and, about the last three questions, i have no idea too. sorry. :c
but, in my opinion, i think vampires can survive under spotlight because
from what i've seen in twilight and thai movies, they survived and act normally like humans in nirmal
spotlight.