Occasionally I'll do a virus scan on my computer just to see if one is found. So far I haven't found a virus -- which is a good thing. There are several programs available to do a virus scan. What I've recently been using is HouseCall by TrendMicro. Website here. If you'd like to try it, you download a small program. When you open it, it first checks and updates itself to the latest version. Then you run a virus scan. I just did one, and it took a bit over four minutes.
Just something you might consider doing occasionally.