input not erasing old data without notice?
 

Hi,

Here is the problem I need to solve with Excel and hope to hear solution
suggestions from this NG...

I have a sheet named "Gorev" where I enter the "teacher name",
"lesson&class" and "period for this lesson" info row by row for each
different task. This info is then used in another sheet named "Haftaplan"
where the top row holds the period labels, A:A column holds the names of
teachers while the matrix region (area) between these two axis displays the
data of the "lesson&class names" retrieved from lists via the formula

=IF(OR(ISERROR(VLOOKUP(B$3&$A4;GorevTbl2;4;0));$A4 ="";B$3="");"";VLOOKUP(B$3
&$A4;GorevTbl2;4;0))


How can I control my input (may use VBA too) so that there will be no
accidental erasing of previously written data?. That is to say that I do not
want to overwrite an existing lesson activity without notice?.

Sincerely
J_J