Do you mean that each record has more than 1 checkbox? If so, put a piece of code behind each checkbox that locks all the other checkboxes once it is ticked - ie say you have 3 checkboxes - chk1, chk2 and chk3 then behind chk1 put the following code after update of the check box:
if chk1.value = true then
chk2.locked = true
chk3.locked = true
else
chk2.locked = false
chk3.locked = false
end if
Amend and repeat for all checkboxes