Microsoft has recently added a series of themes for users of Windows 7 and Windows 8. These themes include Aqua Dynamic, Forest Macros, Ducklings, Captured Moments, Fauna Dynamic, Garden Macros, Garden Seasons, Recursions, Saplings, and Southwest Sandstone.
You can directly visit Visit the Download Page for download and install them. All these themes support Windows 8 RP, Windows 7 Home Premium, Professional, Enterprise and Ultimate editions. The Microsoft Windows personalization gallery now hosts over 200 themes for Windows 7 and Windows 8 operating systems.
You can download more themes for Windows 7 by going to this section.