Are you looking to for a retro Windows XP project, or are you trying to apply a similar dark futuristic theme to a modern version of Windows ? AlienGUIse for Windows - Download it from Uptodown for free
For raw image formats (like .png or .svg ) that capture that dark, neon-lined aesthetic, asset libraries like the All-Free-Download Alienware Directory host various generic futuristic icon sets. Alienware Icon Pack Windows Xp
Icon files from that era generally carried the .ip (IconPackager) extension rather than standard raw .ico or .dll libraries. Are you looking to for a retro Windows