swap hdd

I recently bought my friend's system as he was moving abroad and I have had some concurrent issues with my motherboard. Before I switched hardware all drives worked and had 95%+ on crystalDisc. Now, my two M.2's and two SSD's work fine, but my two HDD's will not read. I have two questions...

I'm getting a new PC soon and was wondering if it's possible to just swap my current hard drives to my new PC, my hard drives just have my games and other files on them, no trying to swap the os, so I don't have to download all my games again.

I’ve recently bought a new ASUS gaming computer, but the problem is, it comes with a 1TB HDD. My old computer has a 1TB SSD, and is also an ASUS system, so is it possible to just take the HDD out and put the SSD in? They both have windows and I am planning on putting the HDD in my old computer.