Actually before reading your answer I had already tried the following:
- unplug the old SSD
- plug the new SSD with the old one's SATA cable
- booted unsuccessfully (blue screen stating that the system must be repaired)
Then I tried booting from the new SSD again, this time plugged on the new SATA port, and I get the same blue error screen.
So I finally reverted to the first setup: old SSD on original SATA port, new SSD on new SATA port. And whit this setup, when I select the new SSD to boot from in the BIOS, Windows starts just fine.
Is there a way to actually know what disk is actually the one I've booted from once in Windows? Necause I suspect the new SSD doesn't work and the BIOS might switch to the old one without warning me. When I look in the disk manager, I see that the old SSD is named C: and the new one is E:
I'm a little confused here...