The harddrive swap is interesting, but is not the cause. I'd suggest swapping the graphics card or monitor cables over.
The "no operating system" error could be a fault with the way your harddrives are set up.
This thread is now locked and can not be replied to.
Nintendo Switch review: Hands-on with the intuitive modular console and its disappointing games…
1995-2015: How technology has changed the world in 20 years
This abstract video touches on division in our technologic world
Best alternatives to iTunes for Mac | Best music players for macOS: Free your music from the…
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.