Question Why given computer became so "slow"? (including context)

[MaxT2]

I recently replaced my computer with a new one. But as I keep using my previous generation computers as "secondary machines", old main computer became new "2nd computer". (It is actually the one that is currently described in my signature.)

As the computer got "demoted" I removed a data-only NVMe drive that I added to the new computer. And I changed the old-computer's location (physically I mean).
Which mean sthat it is not connected to the same peripherals as it used to (monitors*, USB hubs, scanner, printer etc... which I connected to main computer)
(* thought, regarding monitors, it keeps a connexion to the same TV, on HDMI 3 instead of HDMI 1, and his only actual "PC monitor" is the same model as one of the monitors when it was the main PC, so there should be nothing new there.)

What I don't understand is that this since I made this move now-old-computer got very very slow the following ways:

• shutting down may take time
• turning on always takes a lot of time (it feels like the computer receiving a major OS update every time I turn it on)
  • If not stuck on black screens:
  • Reaching Windows 10 login always takes long minutes.
  • Sometimes it gets stuck on "Windows welcome background image".
  • Loading the system after logging takes long minutes.
• After starting Windows, the first actions usually cause controls to freeze for some time, again, it may be for minutes (be it file explorer, or Windows start/search menu, or anything.)
• It "sometimes" shows error messages. (remembered from head: "The tablet is not working properly." ... which table is it talking about? I do have a Wacom graphic tablet, but this one has not been connected to the PC for a year of so, so why complain now. "The component group is not in the accurate groups" (x5) or something like this...)
• After all of these, after a random 15 minutes, the PC feels ready to work as good as before...

I guess that when I'm sure everything (data and config) is properly transferred to the new PC, I will reinstall this OS. But I'm wondering if I can do something to improve this one.

 

[helpstar]

maybe some os partitions mbr or similar to load windows was on the nvme drive you removed and after windows tried repairing it and wasn't that successful. maybe using an old restore point to get running itself again

 

[MaxT2]

Thank you. I think I had set the NVMe drive to avoir "system cache" on it or something like that. Not sure, but does it change antyhing?

I guess I prefer to go over a reinstall instead of restoring a "point" and having to re-figure out whatever I have actually changed in between...
I never actually used restoration points so I'm not sure where that would be leading actually.