Title related.
Here's the whole story:
I wanted to give my brother an upgrade from his old Pentium build, and I had an old HP machine with an AMD A8 7600 lying around. He hands me his PC, and I swap the Motherboards. The CPU and Coolers stay on them, but the RAM, Drives and PSU stay the same between the builds. I boot it up, and...
"No boot device."
Alright. Maybe it just doesn't like his drive?
I plugged in my personal windows boot drive, as it's the only one I have at the moment. I boot it up on this drive, and...
"No boot device."
Strange. Eh, he can deal with his Pentium while I figure this out. I put the builds back together, including my personal one. I give him his PC back. I turn mine on, and...
"No boot device. Try unplugging any drives without a Windows boot on them."
Ok, this is kind of normal. Doing this helped last time, and...
My personal build, which booted fine before I plugged it into the motherboard from the only HP PC in the house, was now not recognized as a boot device. My brother's PC was having the same issue.
TL;DR: After swapping parts from several builds, several of my drives no longer boot windows after being plugged into a motherboard from an HP PC.
I have a theory that something on that motherboard is killing any drive it doesn't recognize. If that is the case, this is genuine cause for legal action against HP.