How to rename windows system folder from "WINDOWS" to "Windows"

Option 1: Get into Recovery options Command Prompt and rename the Windows directory by running ren D:\WINDOWS Windows. (Ref: Booting into Windows RE)

Note that the Windows installation drive would be different when seen from WinRE. If Windows is installed in C:\ then it would appear as D:\ when in WinRE.

Option 2:

Open Notepad (as Administrator), copy the following lines:

[.ShellClassInfo]
LocalizedResourceName=Windows

Save the file in "C:\Windows" directory, as desktop.ini

Then from an Admin Command Prompt run:

attrib +r C:\Windows

That should do it!