Extending Conditional Formatting not working in all cells?

Hi

I have a drow-down list in Cell A1 of an excel worksheet. When I select a particular value in that cell (using the drop-down list) the cell changes color depending on the value. I've used the format painter to extend the change in formatting across the whole row though some cells arent changing colour (actually this applies to whole columns because I've used this drop-down list in the whole of column A).

This occurs after I've pasted some data into the excel worksheet. I've tried paste special: Values only, Values and Number formats, forumlas , pretty much everything and every time paste data into the worksheet it plays up and some cells in some columns won't change colour.

Is this a bug in excel as I can't seem to find what the problem is?

Thanks in advance.
danny2000