Notification popup every time a cell to change certain color.

Hello, my English is not good, so I'm using google translator, sorry about that.


I am creating a spreadsheet where is the organizational chart of my company, set up conditional formatting so that every time the date of some employee contract approaches change the cell color to dark red (RGB 255,51,0).

So I need a code for every time some spreadsheet cell is that color, notify me with a popup, saying a message.

The biggest problem is that the code would have to do a trace on all worksheet cells, do the column and right lines with information that changes color.

I hope I have made clear, thank you all.