|You've been hit with a scam and likely more than a few pests now reside in your OS.|
One other utility to run at this early stage is the Kaspersky Rescue disk. (This is Linux based disk.)
and download the free ISO burn to a DVD. You boot with that DVD and it will load itself into RAM only. It will then go online and update itself after which it will scan the system fully. The hard drive is merely a resource for the RAM installed Linux based OS.
There are more than a few pests which cannot easily be defeated/removed when widows is up and running. Running the Kaspersky disk (or one or two other similar disks) does generally find/delete them.
Johnw will take you through (very likely) quite a lengthy clean out routine. Stick with it as it will resolve the current problem and likely a few others too... And do remember to keep "any logs" generated as they are invariably useful to know "wot's wot etc."...