gridview with itemtemplate checkboxex in asp.net

Question

Hi please help me resolve this very urgent..

I have a gridview with courses to register in a semester with various fields like days(mon.tues..) and timing(1:30 to 2:30). A student has to select the courses by checking the checkbox and press the submit button. there are time clashes between few courses, I want to add the functionality where when one checkbox is checked then a method should be called where the timing of the other courses are compared with the selected one, and the same timing courses corresponding checkbox should be disabled.