Prevent duplicates Excel user form

Hi

I need to check whether a value in one text box ("txtRCAname") OR a value in a second text box ("txtRCAname") in a userform already appear in my data.

The value in "txtRCAname" needs to be checked against a column of data in a worksheet called "RCA_Data", column A2:A1000.

The value in "txtRCAcode" needs to be checked against a column of data in the same worksheet called "RCA_Data", column B2:B1000.

If a duplicate is found, I would like a message box to appear with an appropriate message.

Thanks!

Sorry - second text box is called "txtRCAcode"

Thanks, will this work for any input i.e. not just a numeric input? Because my txtboxes are not numeric.

Also, any ideas how, in the instance of a duplicate appearing, the user could choose to accept and the user form would overwrite the data??