Start pc and showing black screen press alt+ctrl+delete button then open task manager

click file select new task  create new task type explorer.exe

click ok  know windows screen  will come then open cmd as a administrator  and type sfc /scannow

and scan full system after reboot system ok

note: some windows if you open cmd automatic restart system so  plese scan full syatem kvrt tool is the best kvrt full scanning take time but system 100% ok

Download  Kaspersky Virus Removal Tool (KVRT)