Call function in Program.cs

Question

i have a program that runs in a continual loop as it uses open gl to draw graphs from xml files. however i need to call a function from a seperate class. the function starts parses a seperate xml file that has configure data for the graphs so needs to be parsed before the main form has loaded so it cant go in formload. idealy it needs to go in to Program.cs but i dont know how to call it. any help wpuld be good
thanks in advance