Windowscore is an aesthetic similar to webcore or Nostalgiacore but focuses more on Windows' oldschool look: rounded blue edges, chrome colored themes, messeging softwares, etc. It's porpuse is to induce a sense of nostalgia to old Windows' users; reminding them of simpler times.
The main visual aesthetic that this category follows is the rounded blue edge windows that old software on Windows XP archived, the sharp looking windows that software appeared on Windows 95/98, or the transparent background that Windows Vista is much known for (in terms of looks).
This may also include early 3D examples from Windows' screensavers or commercial, ads for any of Microsoft's product or even software that characterized the old Windows OS's.
Windowcore relates itself audibly to Vaporwave, since usually the people who follow this aesthetic are in mayor part resposable for the vaporwave movement.
As odd as it sounds, there's a genre that the people who follow this aesthetic have created: The mockup bootup/shutdown screens.