Hi,
I have a XLS file with many sheets in that. What I am looking for is - whenever that XLS file is opened (i mean any sheet) then if the file is opened for the first time in a NEW MONTH then a dialog box is displayed with a custom message and OK & cancel button. Pressing CANCEL would not display that message again for this given month but Pressing OK would display this message again and again until CANCEL.

This process should repeat for any new month.
Pls. someone help me write that type of program/macro.