Draging the formula doesent work the way I want it.

Hi

This is my problem:

I have list A and B, in C i want the following to be calculated:

__A___|___B__|___C____
__x___|___a__|___a*x__
__y___|___b__|___a*y__
______|___c__|___b*x__
______|___d__|___b*y__
______|___e__|___c*x__
______|______|___etc__
_________________etc.__

My problem is to find a formula that I can wright in the first lines of column C and then drag it all down (I have like 1024 rows in C) and it takes just to long to wright it all by hand!!

Glad for any help!

//Toby