O.k guys not much info here. All I remember is a young good looking actor(not jim carrey) finds out he is a vampire during the movie. One scene I remember is him sitting in class with shades on and the song "The futures so bright, I gotta wear shades" is playing during this little montage which includes keepin blood in a refrigerator. I also think but am not sure ther is an older vampire tutoring him like a grandfather or something. Its a comedy/horror and not a great movie just like most the movies from the late 80's or early 90's.
Sounds like My Best Friend is a Vampire (http://www.imdb.com/title/tt0095684/).
I'll second My Best Friend Is a Vampire
Without a doubt, My Best Friend Is A Vampire.
The lead character was Robert Sean Leonard and the elderly vampire was Rene Auberjonois