Yes, you can change the color of all series in an Excel chart in one go. Here's how you can do it in Excel 2000:

1. Select the chart by clicking on it.
2. Click on the "Chart" menu at the top of the screen.
3. Click on "Chart Options".
4. Click on the "Colors" tab.
5. Under "Color Palette", select "Custom".
6. Click on the "Modify" button.
7. In the "Color" dialog box, select the color you want to use for all series.
8. Click "OK" to close the "Color" dialog box.
9. Click "OK" to close the "Chart Options" dialog box.

Now all series in the chart will have the same color. If you want to highlight a few series, you can change their color individually by selecting them and then right-clicking to bring up the context menu. From there, select "Format Data Series" and then choose the color you want to use for that series.