Help, I've fallen and I can't get up....

I must have broken my VFP and I don't know how to fix it. I used to be able to change something on a form and run the form from the project mangager to test my changes. Now I have to build an exe everytime for the form to reflect my changes. This is annoying and time consuming. I'm assuming I changed some setting, but I don't know what it is. Can anybody help me???