Swapped mb/cpu, 100% disk usage now

[screencut]

I just put the hdd of an old hp i3 system into a new case with a different motherboard/i5 cpu. Everything booted up fine until I noticed that windows 10 is running really slow. Task manager states the drive is going at 100%.
I noticed norton was on top of drive access and ended that task, which only brought the usage down to about 96%.
Does anyone have any clue why this has happened? I know it should have been a fresh install, but surely that wouldn’t be the cause? Is there perhaps somewhere I’ve went wrong on installation of the hardware in to the new case? Any suggestions would be appreciated.

 

[Colif]

1. Do you still have the old PC? Do you know if your license was linked to hardware or an email address? I wonder if windows 10 is still activated

2. Though Win 10 is better than previous versions when it comes to just being moved from 1 PC to another like it, its generally a better idea to fresh install on brand new hardware as you will have old drivers on PC that match old hardware. I would suggest a fresh install and it should fix the disk usage

 

[screencut]

1. Do you still have the old PC? Do you know if your license was linked to hardware or an email address? I wonder if windows 10 is still activated

2. Though Win 10 is better than previous versions when it comes to just being moved from 1 PC to another like it, its generally a better idea to fresh install on brand new hardware as you will have old drivers on PC that match old hardware. I would suggest a fresh install and it should fix the disk usage

Thanks for the suggestion. I’ve just been told that after defragging the drive and disabling Norton that disk usage sits around 7% now and the system is no longer slow. Still recommend a clean install after that?

 

[Colif]

Its up to you really... Curious about answer to number 1

whats showing in settings/update & security/activation?