How To Use Windows 7 Button Changer:
1. Run the tool as administrator. If you have run this tool for the first time then it will create a backup of the unmodified “explorer.exe''.
2. Click Select & Change Start Button. When it asks for the new start orb bitmap, either choose from any of the sample start orb bitmaps provided or choose the one you have.
3.The Windows Explorer will now restart automatically and you will be able to see the new start orb/button which you chose.
4. If you want to revert to the original start orb then just click Restore Original Explorer Backup.
Here's 47 free Start Menu orbs for you. Download and enjoy.
Here's the complete video tutorial of changing Windows 7 start menu by using Start menu Changer-