By default, Excel uses your Documents (if you use Vista) or My Documents (if you are using XP) directory as the location for saving files. To change the default file location, follow these steps:
1. Click the Office Button.
2. Click the Excel Options button.
3. In the left pane, select Save.
4. In the Default file location textbox, input the path to the desired directory that will be the new default location.
5. Click OK.