How To Remove System Security Virus Infection -

Once in Safe Mode, run a deep scan using a trusted "second opinion" scanner. You can download these on a clean computer and move them via a USB drive if the infected PC's internet is blocked. Cleaning an Infected Computer of Malware

Hold the Shift key while clicking Restart from the Power menu. Select Troubleshoot > Advanced options > Startup Settings > Restart , then press 5 or F5 for Safe Mode with Networking. How to Remove System Security Virus Infection

Safe Mode loads only the essential files and drivers, which usually prevents the rogue software from starting up. Once in Safe Mode, run a deep scan

Here is a solid guide to removing it and reclaiming your system. Once in Safe Mode