Thanks for your answer.

1. Data Filter Advanced Filter with list range as the table and
click unique records only. 2. Mark these unique records by filling down
an "X" to the right of the data.
3. Now choose Data Filter AutoFilter and select blanks in the "X"
column.
4. Copy the selection to another sheet and select Data Filter
Advanced Filter with unique records only on the new sheet.
It doesn't function. It's likely that I do anything wrong.
Especially I don't understand when and where to fill down an "X".

b) Not sure what you mean, but to see the differences between columns,
select the columns by holding down ctrl key and clicking on column
headings e.g. A,D,F,H,...
Then press ctrl+\ (Edit Goto Special Column Differences) to
select the differences with the last column selected which you could
highlight in a different colour
It doesn't work either. :-(

Describing my problems more simply: In both cases I want to find out
whether there are any rows (records) repeated. In the case a) I want
to know whether there are any entire raws repeated. In the case b)
I want to know whether there are any rows (records) with the same
value in the column containing the identification of the data.
In both cases, if there are any, I want to know which ones.
That's all.
Sorry for my poor English.

Regards
Neo