Your PC got hijacked by a stubborn trojan that uses CPU resources in the background to mine coins, sorry pal it's near impossible to remove this trojan completely, I suggest you format your HDD, use NICEHASH Miner next time, it's more safer and it support zcash mining
Lol.... I didn't format yet but physical memory is 43% without doing nothing, what do you think?
https://prnt.sc/rh33sd