@romms
Hi,
Did you have a backup disc?
If so, you could press f12 which shows boot menu. From that select DVD so that you can do it from it. Them select the do it from system recovery disc option and then all the process of restoring will start and your system drive will start formatting and will be replaced by the backup what you have inserted.
If not, you will need a Windows 10 boot disk.
Installing Windows 10 using the media creation tool - create media then boot with it.
https://www.microsoft.com/en-au/software-download/windows10
For your reference:
https://answers.microsoft.com/en-us/windows/forum/windows_10-performance-winpc/windows-10-error-code-0xc000000f/765e013a-f3d0-472b-a92f-2f0ec14b0e6c?page=1
Hope above information can help you.
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