Yes, you can create a stack bar chart with positive and negative numbers in Excel 2007 and have the Y-axis values reflect the total values of each data set. Here's how:

1. Enter your data into Excel. In your example, you would have two columns: one for the component names and one for the gross profit values for year one and year two.
2. Select the data you want to graph, including the column headers.
3. Click on the "Insert" tab in the ribbon.
4. Click on the "Stacked Bar" chart type in the "Charts" section.
5. Excel will create a basic stacked bar chart. Right-click on the chart and select "Select Data" from the menu.
6. In the "Select Data Source" dialog box, click on the "Add" button under "Legend Entries (Series)".
7. In the "Edit Series" dialog box, enter a name for the series (e.g. "Year One Gross Profit").
8. In the "Series Values" field, select the gross profit values for year one.
9. Click "OK" to close the dialog box.
10. Repeat steps 6-9 for the gross profit values for year two.
11. Click "OK" to close the "Select Data Source" dialog box.
12. Your chart should now show two stacked bars, one for each year. However, the Y-axis values may not reflect the total values of each data set.
13. Right-click on the Y-axis and select "Format Axis" from the menu.
14. In the "Format Axis" dialog box, select the "Axis Options" tab.
15. Under "Vertical Axis Crosses", select "Maximum Axis Value".
16. Under "Bounds", enter the total value of the gross profit for year one in the "Minimum" field and the total value of the gross profit for year two in the "Maximum" field.
17. Click "Close" to close the dialog box.
18. Your chart should now show the total values of each data set on the Y-axis.

That's it! You now have a stack bar chart with positive and negative numbers in Excel 2007 that reflects the total values of each data set on the Y-axis.