Right-click on the 750 MB unallocated space and create a new simple volume. Assign the drive letter S:
Format it as NTFS. Uncheck "quick format."
(Post a screenshot)
Once done, open S:\ in File Explorer.
Create the subfolder: S:\Recovery\WindowsRE
Copy winre.rim to the above folder.
From admin Command Prompt, run:
- del c:\windows\system32\recovery\reagent.xml /a
- reagentc /disable
- reagentc /setreimage /path S:\Recovery\WindowsRE /target C:\Windows
Post the output.