I really messed up my project. I have 2 copy of the same class library in 2 different folders. Accidently, I have added objects into my form, from both classes (which I should not have done. I was suppose to only use 1 of the class library). I think this is why when I compiled my codes, the application does not run at all. It gives me a 'class name is invalid' error. I've checked my objects (in my form class) & have found some objects has the wrong parent class (class name is the same, but it is from a different folder). I've tried looking into the class browser, & there I can check parent classes of my objects, but I don't know if I can just change the parent class to the correct pathname (file name of the classlib is the same). Can anybody help???? Thank you all!!!