Hi, well mason asked if you were running home or pro. It appears you have home, so no group policy editor.
What do you want to do, get rid of Cortana? I don't use it myself and have completely removed it, so it doesn't come back even after a feature update.
It might be a problem with a third party process I would try a clean boot, and see if the problem continues.
I don't see the errant usage from the info I had you post, so please when the problem persists show us the process from task manager OR run this cmd (both would help) Cmd as admin (as shown), copy paste & attach as per previous post.
wmic process get Caption, CommandLine, Handle, HandleCount, PageFaults, PageFileUsage, ParentProcessId, ProcessId, ThreadCount /format:List > 0 & notepad 0
You need a bit more then the one reg mod(firewall rules have to be tweaked, and to avoid event viewer errors and the process rebirth you need to rename it, this is a bit tricky, you have to be quick, also need to mod registry permissions to be totally rid of this, I would not trust anyone other then an expert to do this.
Also from a cmd prompt copy and paste this cmd:-
reg query "HKLM\SOFTWARE\Policies\Microsoft\Windows\Windows Search" > 0 & notepad 0
Post the notepad output here (just copy paste into your reply) this will show if you added the one reg mod properly (it is a correct mod).