Try the Windows 10 refresh this PC AFTER you have backups of what you can't lose. Refresh shouldn't touch your files, but as malware and worst is out there, effects could be dire.
Read https://www.howtogeek.com/75901/how-to-use-refresh-and-reset-in-windows-8-to-easily-reinstall-your-pc/
Okay so i downloaded a custom theme from Deviart. When i ran the theme it brought me to a blue screen and please wait like normal. i got an error message that said the application failed so i clicked okay. it brought me back to the login screen at the wrong screen resolution. i logged in and it brought me to a grey screen. so i restarted the PC multiple times, and it would boot up then once i got to the login screen it was a grey screen. so i put in my original windows 10 download CD and entered safe mode. I deleted the theme files through the CMD. so i left safe mode and booted up my PC in normal mode. That fixed the grey screen. but now when i go to log in it goes to a black screen as if it was going to bring me to my desktop but then it shoots me back to the log in screen as if i just started my PC. So i went back into safe mode and used the trouble shooting thing. i rebooted still the same problem. so my next theory was try to run on of the default windows themes. so i went back into safe mode tried C:\Windows\Resources\Themes\aero.theme and i get a error message saying no such interface supported. i tried it with aero,theme1,and theme2.

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