Excel process remains running after COM has finished

Question

Hi All

I'm trying to create a program that writes some data to excel and creates a graph. Currently when I am finished with the COM I close it by doing the following:
if (xla != null)
{
xla.Quit();

xla = null; // Ends connection
}

Is this what I should be doing? I don't think it is, as every time I run the program it opens another Excel process that does not close after I have finished with the COM. What should I be doing? Your thoughts and tips are appreciated!

Cameron