Over the years I've seen this due to a few things. I can't tell you what it is this time.
CPU isn't in the motherboards support list. HDD issues (too many to get into but to test I run it from a good shop drive.) Out of date BIOS. Cracked and/or infected OSes.
Now you can cause this to happen with conflicting or just bad apps but you only listed so much so I have to share all this and hope you find it.
I was having high cpu usage on windows 10 with an i5 4690 so I bought an i7 4790k and my cpu usage is still ridiculously high and by high I mean 90-100% when I go to a page or watch a video. I was wondering what would cause this. I was thinking that I had a bad cpu and now I don't know what's the issue.
My motherboard is a z97a.

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