If all else fails - or after scanning with standard windows based antivirus programs and you still have doubts, try the AVG Rescue Disc.

It is a good idea to make one of these for future emergencies anyway, in case a virus ever crashes your Windows.

It is a free download to create a bootable USB stick or CD. When starting your computer with this inserted it actually boots with a simple Linux OE on the stick or disc, which then allows you to do a full scan of your computer before Windows loads, allowing a scan of the bios and all of Windows.
Some viruses that get into your system while your antivirus is outdated or disabled for some reason, can avoid detection as they load before Windows does.

It sounds a bit daunting at first, but if you watch the basic "how to" videos on You Tube first it is actually quite easy to do.

You can get the download here https://www.avg.com/en-ww/download.prd-arl

And watch the how to vids here https://www.youtube.com/watch?v=fGX-592qty8