In my desktop PC I have an SSD where I installed Windows 10 many years ago. Later I purchased an nvme ssd, where I also installed Windows 10, and I can choose which Windows 10 to launch at boot. Both disks are using MBR, not GPT.
Fast forward to now, I want to remove my SSD and just keep the nvme. I launch Disk Management and I can see the SSD (that I want to remove) with the three typical partitions: system, main and recovery. But the nvme only has one partition, the main partition, taking the full disk size. It's labeled as "Healthy (Boot, Page File, Crash Dump, Primary Partition) "
I've tried unplugging the SSD (disk 0 in the image) and the system does not boot, apparently because it's missing the system partition. How can I add (or move) a system partition to the nvme (disk 3 in the image)?