I have a graph:
<%
Set oChart = CreateObject("OWC.Chart")
Set c = oChart.Constants

oChart.Charts.Add
oChart.Charts(0).Type = oChart.Constants.chChartTypeColumnClustered
%>

How can I change the color of the columns???
What is the code??

I'm not sure what OWC is but I've got a free barchart ASP class (no components) downloadable from my Web site at http://www.bullschmidt.com/barchart.asp to help turn data stored in a table (or SQL statement) into a barchart and you can explicitly set the colors of the bars or else just use the default colors:

' Fill aChartSeriesColor.
aChartSeriesColor(0) = "#0000FF" ' Could put in something like "blue".
aChartSeriesColor(1) = "#CC0000" ' Could put in something like "red".
aChartSeriesColor(2) = "#FF9933" ' Could put in something like "orange".