Well can use Task Manager (ctrl-alt-del, select Task Manager) to see what the processor (CPU, Memory, HDD) is doing, obviously something is slowing thens down.
Personally, I'd try temporarily removing any third party AV (e.g. AVAST) and make sure there is nothing else loading (McAfee, Symantec). One fast way to kill performance is to have two AVs butting heads.
Now anything with a rotating drive is going to be slow loading. I have one machine with removable drives from the last century (easy to test multiple OSs) and it takes about two minutes to boot Windows 10-64 1703 now.
OTOH my R3 (Intel Atom 4-core CPU, 2.4GHz max, ventless design) now has 8GB of fast RAM and a Samsung EVO SSD. Is running the same OS and boots in seconds.
Both of these are running Windows Defender, EMET set Paranoid, and the UAC set to prompt everything. For me this is the best combination. The R3 now runs with an i7 having a rotating drive, the SSD makes that much difference.
Just a thought.
