Originally Posted by
piggybank
The SSD wants to dominate even though I have set BIOS and BOOT to use the HDD.
I have gaps in my understanding here, however one possible reason for this might be that the PC is configured for UEFI boot or Legacy BIOS boot and one of the disks is the other one.
Legacy BIOS boot - MBR on Disk. Master Boot Record
UEFI boot - GPT partitioning Scheme
This seems like quite a decent article.
https://www.howtogeek.com/56958/htg-...lace-the-bios/
If you start changing the BIOS settings make SURE you record everything so you can put it back after.