Is It Possible Write A Formula In Excel To Execute Only Once.

What I Have Is A Cell Using COUNTA And Then A Cell Using The COUNTA Cell With An IF Statement. From Another Cell I Am Using VLOOKUP Based On The IF Statement Cell And The Return Is NOW.

This Formula Needs To Be Enter Multiple Times In The Sheet But Because Of How It Is Written The Formula Will Forever Change. I Need It To Input The Time At The Time Of The The Information Is Entered For The Counta Statement. If You Can Help Out That Would Be Great. Thanks