All vampires are effected by sunlight and fire, but the older a vampire gets, the less he is affected by these. The oldest Vamps (4000 years plus) are not burned by the sun, merely browned (eg. Akasha and Enkil, and Lestat ) .And children of millennia (1000 +) are able to withstand some fire. (eg Pandora, Marius, Mael)In fact, they could walk through a huge bonfire and walk out the other side only cleansed, but if they stayed in it, they would eventually die.
The Blood is what animates a Vampire. If All the blood of a vampire is drained, the vampire is as good as dead. This is extremely difficult though as vampires contain huge amounts of blood and in some cases it would take hours to drain a vampire fully. Now, here is the tricky bit. All vampires are immortal. BUT, say for instance, a blood drinker was to be cut in half. Slices in two horizontally, then both halves would crawl around until they were finally joined back together again. Meanwhile, the blood loss from it would render the vampire almost useless. If an arm was to be cut off in battle, the vampire could pick the arm up and rest it on the stump, but it would take a long time to heal back on, even for the eldest vamp. (eg. Enkil, King of the Egypt, had an arm severed in battle.. he picked it up and put it back on, where it healed) Lost limbs do not regenerate. And the big question, the Beheading. If a vampire is beheaded, you might as well call it dead. For without the head on the shoulders, the creature can do little, for the shock of the instant blood loss would all but render the vampire unconscious. (eg, Akasha, the very first Vampire was attacked by Meakre , and her head was severed. She was powerless after it was severed and could not even reach the head to put it back on..)
However, If a limb is cut off and burned, the vampire may take the same limb from a mortal and use it. Although, the mortal arm will eventually die and need to be replaced. (eg. Maharets eyes were taken from her before she was given the Dark Gift. Until Thorne gave her his, she uses mortal eyes, but these give her irritation because the demon blood does not keep them alive)