Forms :: Autofill A Textbox With Current Date

Short version: I would like to know when that formula was filled out.

Long version: What I need to do is Auto-fill a textbox with the current date and time when I fill-in a combo-box and press enter/tab. Each date needs to be individual, once the date is filled in via event it should not be changed, then the next page of the formula needs to have an individual date...and so forth. In addition it would be nice if the date could not be changed at all, so no one can temper with it, for instance pressing enter again on the combo-box.

Something like this:
Formula page 1:
Name:________ Date:________
Name: Jon_____ Date:________
*press enter*
Name: Jon_____ Date: 08.04.2015; 11:31
*press enter*
Formula page 2:
Name:________ Date:________
Name: Jess_____ Date:________
*press enter*
Name: Jess_____ Date: 12.04.2015; 16:12
*press enter*

Solved all but 1 problem, I just need to find a way to stop the Date field from updating every time I update the Name field after the initial date is filled in.