DeviantART released some Windows 7 themes for Windows XP deskyp. If you're running Windows XP SP2 or earlier, you can download a Windows 7 theme and UxTheme Patcher at MegaLeecher, and if you have SP3 installed, you need to install a different patcher. Once you’ve downloaded, unzip the file and click the multi-patcher file in the UX Theme Patcher Folder and then click the Windows 7 M1 VS.msstyles file in the Windows 7 M1 VS subfolder in the Themes folder. Finally, reboot your system, you should be able to see Windows 7 theme.
Source:→ Shell Extension City