Really curious how did you conclude that it's a virus which is restarting your PC. Very most of the time it's actually the overheating or the power supply unit doing it. Virus would be highly unlikely, unless you have been using your PC in very careless way.
Also, since a week has passed, have you done your scanning yet? It takes just a moment to download Malwarebytes with Avira and launch the scanning. Avira's results will almost certainly be exactly the same as Norton's. There is really no point paying for anti-viruses these days for casual user if the OS, internet browser, and the anti-virus/firewall built in the OS (or their free alternatives) are providing excellent protection.