Graphical user Interface problem

Hi ,
I am trying to calculate simpsons rule of integration. when i use normal empty project for console application my code works alrite, but when i use windows form application, i creat 3 check boxes for 3 different type of simpsons integration and 3 input boxes one for upper value, one for lower value and when for no of n values . and a calulate button . i put all of my code behind calculate button, but when i run it it runs for a second like an eye blink and then goes back to normal form .also when i run it my form bottom splits into two portions right one saying Immediate window and closes down within no time , it shows me no errors as well, and my second problem is when i try to assign the value of 'a' to TextBox1.Text , i cant find Textbox1.Text in the popdown menu while typing it.
Please help ASAP?