how to lock a data entry

[mtp3i]

Dear All,
I need a help how to lock a data entry. I tried to use beforeupdate event and gotocontrol but failed. I want to lock data entry, so that we can't input any word to fields before clicking start entry for time stamp. So that time stamp will be accurate and people won't forget to click it.



Thank you for kind response.

[Micron]

open the form with the necessary controls disabled (or locked if you prefer, but that is not so user intuitive)
Enable/unlock them upon button click. It doesn't need to be any more complicated than that if you're only dealing with a few.

EDIT
or you could simply time stamp just before the record is saved to the table.