If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm
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Short course:
Hit alt-f11 to get to the VBE (where macros/UDF's live)
hit ctrl-R to view the project explorer
Find your workbook.
should look like: VBAProject (yourfilename.xls)
right click on the project name
Insert, then Module
You should see the code window pop up on the right hand side
Paste the code in there. (But change the name from TestMe to something
significant.)
Now go back to excel to test it out.
Tools|Macro|macros|select that macro and click Run
Save your workbook before you run the macro--then if you have trouble, you can
close without saving and bring things back the way they were.
Note: DateSerial(2006, 1, 1) is dateserial(year#, month#, day#)