Yesterday i upgraded to win 10 using the installator from website , and i choose the option to keep all my data. Disk usage on startup is at 100% and system runs slow , i turned off windows defender and firewall , reinstalled all drivers and tried basically every fix i could find on internet yet the problem still remains. I think that the old files from win 7 might be interuptting something at startup but idk .It definetly isnt hardware related and my hdd has zero errors. I ran into some dudes that had the same problem and they upgraded the same way i did.