Timer in MS Word Form

I dont know if this question should be ask here but I would just try for it involves also a code.

I have Microsoft Word form document. The contents of this form are questions with corresponding textboxes for their answers. What I would like to have is a count down timer built on it so that when the time ends a message box comes out asking the examinee to stop answering. When the OK button in the message box is clicked, the form will be automatically send to my email add.

I feel this difficult for me to do but I'm sure not for you guys. Please help me to have it. At least, I can also improve my style in giving a test to my students.

Thank you so much for any help.

P.S. - If you think there is another way to do it, I mean using other program, as long as the purpose is still there, I am so willing to accept it.

Yours sincerely