The Start orb in Windows 7 looks pretty cool, in my opinion. However, should you find it ugly and repulsive, you can easily swap it for something else with the Windows 7 Start Button Changer. Download and run the portable app as administrator (right click > Run as Administrator) to get the window shown below :
In the Open dialog that’ll launch, navigate to the place where you extracted the contents of the zip file and select any of the 10 sets available.
Windows 7 Start Button Changer [The Windows Club]