Query question!

Does anyone know how to write a query to get out the sum of a whole table column? ex. I'm playing around with a database where customers can buy stuff. I have a table where I save all the invoices, but now I want to write a query that sums upp all the prices in the price column in that table. Is

windows 2000

imppossible ti remove the service also. It can´t be removed event thoug I have uninstalled MySQL. How can I get MySQL running on Windows 2000? / Micke