Changing color scheme of Office 2003 running on Windows 7 OS

Seems like it's only possible on Windows XP/2000, can't find anything for Windows 7.

Change Office's appearance - Support - Office.com

Possibility for Excel here:
Change the color palette in a workbook - Excel - Office.com
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When you change a color in a workbook palette, any element formatted with that color is changed throughout the entire workbook.
Change a color in a color palette

1. Switch to the workbook that contains the color palette you want to change.
2. On the Tools menu, click Options, and then click the Color tab.
3. Click the color you want to change, and then click Modify.
4. Do one or more of the following:
   
   • To replace the selected color on the palette with a different standard color, click the Standard tab, and then click the color you want.
   • To change the hue or another aspect of the selected color, click the Custom tab, and then change the options.
   
   

Notes

• To restore the default color palette, click Reset on the Color tab.
• If you copy an object or cells with a custom color to another workbook, the custom color is replaced by the color in the corresponding position on the other workbook's color palette. To retain the custom color, either copy the customized color palette to the other workbook or change the corresponding color in the workbook.
• To replace the default color palette in new workbooks, change the color palette in the default workbook template or in the custom template you use to create workbooks.

Copy a color palette to another workbook

1. Open the workbook that contains the color palette you want to copy.
2. Switch to the workbook that you want to copy the color palette to.
3. On the Tools menu, click Options, and then click the Color tab.
4. In the Copy colors from box, click the workbook that contains the color palette you want to copy, and then click OK.