STOP WINDOWS UPDATE
In RUN type “services.msc“, the services page will be open
Search for “Windows Update“
Click “Stop” if status is “Live” or “Checking/Running“
Select “Disabled” on “Startup type“
Apply & Restart
Do it again and make sure that it is disabled
Also if you want you can disable more services..

source: http://1stminingrig.com/best-windows-setup-configuration-tweaks-for-mining/