I tried this but it did not work I'm sure I've done something wrong. I
pasted the formula in visual basic and saved would that be it? Help
Please

It works for cell B2, and assumes that B2 has some Data Validation attached
to it, and must go in the worksheet module (*not* an ordinary one).

For info on worksheet events, see
http://www.mvps.org/dmcritchie/excel/event.htm ; for info on DV, start at
http://www.contextures.com/xlDataVal01.html

Rgds,
Andy