And if yes, you might want to make the enum and the variable that is of enum type static. Or create an instance of the class and put the switch in a non-static method.

Also, in switches on enums, you don't need to (and AFAICR can't) prefix the constants, i.e. it's just
Code:
switch(appState)
{
case MAIN_MENU:
And another thing I've hinted at: because of the enum constants' name lookup rules, giving them a common prefix ought to be unnecessary.