You can use a macro...

J.E. McGimpsey shows a way to put a time stamp on the same row when something
changes:

http://www.mcgimpsey.com/excel/timestamp.html

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm

If you want to read more about these kinds of events:

Chip Pearson's site:
http://www.cpearson.com/excel/events.htm

David McRitchie's site:
http://www.mvps.org/dmcritchie/excel/event.htm

Joker wrote:

I am trying to find a formula which will automatically insert the current
time into a cell based on if there is info in another cell. In cell B48, I
have the formula =IF(C480,NOW(),""). The formula works and
displays the time, however, it keeps changing as I make other changes on the
worksheet. Is there anyway to keep it from changing times? Thanks for your
help.

--

Dave Peterson