Based on what you are saying I would be looking at Crypto Mining Malware maybe has infested your computer. If you are not aware of how to deal with malware, bleepingcomputer.com is a great reputable and free resource. There are so many bad sights claiming to help. I stick with bleep and majorgeeks.com. I highly suggest you get some proper malware scans going. Sometimes these crypto miners are just driveby miners that run in your browser. This is happening at youtube right now. It has even been in the news. Killing your browser, will shut them down, not just closing the page but exiting the whole browser. Hit ctrl-alt-delete and watch what is using your cpu cycles. If it is browser based to ublock origin by ray hill add on for chrome, firefox and edge does block known drive by crypto miners.