First thing you want to do is disconnect yourself from the internet (either unplug the network cable or disable the wireless NIC if connected that way). If you have access to another PC, you should download Malwarebytes installer
(the free version is fine), put it on a flash drive or some other device you can use to copy it to your PC without using the internet, then boot up your PC in safe mode (press F8 over and over again while the PC is booting) and install/run Malwarebytes. Do a full scan, then reboot with with the network cable plugged in. You may have to run Malwarebytes several times before it finds everything. Just keep running it until it comes up with zero found.