CLICK HERE

1. Run the tool as administrator.
   

1.  
2. Click Change.
   
3. Select the start orb and click Open. You can get some orbs from these links: 1, 2
   
4. The Windows Explorer will now restart automatically and you will be able to see the new start orb/button which you chose. Click OK.

To restore the original start orb click Restore.
You can expand the advanced settings by clicking the arrow at the bottom right corner of the window:

Checking the Add Shortcut In Context Menu option will add an Start Orb option in the desktop context menu so that you can access the tool with one click:

Checking the Add Option In Context Menu option will add an Set As Start Orb option in the context menu of all PNG and BMP files so that you can change your start orb with one click:

Compatibility:

This tool has been tested with Windows 7 Ultimate English RTM SP0 (No Windows Updates) x86/32-bit and x64/64-bit on several computers and works perfect. If you are using SP1 or any Windows updates, check the Replace By Editing Resources option and try.
To create your own start orb visit this tutorial: How To Create A Windows 7 Start Orb
Credit goes to Jeff Bush for the memory patch and resource updater.