Here is a detailed explanation of what we did, since I didn't really spell out every piece previously. I didn't want to make it too confusing at that point in the process, so now is a good time to spell out out in detail.
Here is what we knew starting the process:
We knew that the system was upgraded to Win 11 and all was well for a couple of days (if my memory serves correctly). At that time the system apparently wanted to go into recovery mode but other problems prevented completing that. For example, neither the mouse not the keyboard would work, even though different USB ports were tried (basically all of them).
We did know that the keyboard would work to get us into the BIOS, and once in the BIOS it would work there.
We also knew that it was fine to install Windows from scratch as there was nothing needing to be saved.
What we did not know:
The disk layout (MBR, GPT, or even how many disks in the system). We also didn't know if the system could boot from a USB Flash Drive (UFD) formatted with NTFS.
The plan:
Since the keyboard and mouse were not working, I thought that we could create a UFD with an unattended answer file just to take us up the point where disk selection would take place and then pause. The idea was that if the mouse and keyboard were working at that point in the installation, we could prep the disk at this point, and then continue installation unattended to get Windows fully installed.
If the keyboard and mouse were not working at this point in the installation, I would make a small tweak to the unattended installation to install Windows 100% unattended with remote desktop enabled. If the mouse and keyboard were still not working after Windows was completely installed, this would still give us a way into the system to troubleshoot further.
A note about the UFD: We needed support for files greater than 4 GB, but since we didn't know if this system would boot from an NTFS formatted UFD, we created a UFD using a dual FAT32 and NTFS partitioning scheme. There are other ways to address this, but I've never had this method fail and I already had a batch file that I created to automate the process so that's what we went with.
From here it turned out to be easy. We never needed much of the advanced planning. We went into the BIOS and set USB disk as the first option in the boot order, booted from the UFD, and at the screen that showed us the available disks we found that there was only one disk in the system. We deleted all partitions and selected the unallocated space.
NOTE: Another benefit of pausing the unattended installation at the disk selection screen is that this cause unattended setup to become universal - it will work with both MBR and GPT configurations since we do not need to specify the layout in advance in the answer file.
At this point, the remainder of setup proceeds completely unattended.
After setup was done, the keyboard and mouse continued to work and we allowed Windows to install any updates.
I suggested considering making a good disk image backup just in case this drive is on the way out, but at this point all looks good.
I know I'm throwing out a lot of info here, so please feel free to ask any questions
