Dear Experts

I want to create a log.txt or log.ini or log.xls for my software as:

Suppose some user uses my software in the follwing duration:
27-04-2006 06:00:25 AM TO 27-04-2006 08:30:55

I want ot store values into log file

SNO-----------Start--------------------stop---------
1----27-04-2006 06:00:25 AM -- 27-04-2006 08:30:55 AM
(like three fields)
What procedure should I add into my main prg.
I do not want to use dbf for this purpose.

Please help