Preventing Duplicates

Hi to all.

I hope someone can help me on this. I am relatively new to VBA so not sure the best way to go about this....

I have a workbook with 24 tabs, 2 relating to Jan, 2 to Feb and so on....

Each sheet contains a text column for a individuals name, 2 columns for 2 dates and a numeric field to 2 decimal places, in the same columns but not necessarily the same range. They start in the same place but some sheets may contain more rows than others.

What I would like to do is prohibit users from entering identical info in the 4 columns, on any of the other 23 tabs if it has been entered previously. That's as much info as I have at the moment.

Please let me know if you have any questions.

Thanks in advance

Tom

Thanks Roy.

The spreadsheet is used to calculate sales commissions so there is a tab for new sales and one for extensions for each month.

It was requested to be like this by management and I think this way, its cleaner and easy to read. Could we copy all current data to a scatchpad sheet and check for duplicate there? Ideally it would be preventive but as long as we can run a check before submission to payroll, that would be fine.

Cheers