

To use them, you’ll have to modify Windows system files - uxtheme.dll in particular - and disable the check. If they aren’t, Windows won’t load them at all. Windows checks if themes are signed by Microsoft before loading them.

These aren’t your standard Windows themes - they modify the appearance of window title bars, buttons, and other visual elements. There’s a thriving community of theme-builders who are still creating themes for Windows 7 and 8. By default, Windows will only load Microsoft-signed themes - but you can get around this fairly easily. Windows has had support for themes, also known as visual styles, since Windows XP.
