Viruses have to REALLY bad to require a format to fix it. Also a virus isn't generally intermittent.

My analogy for format reloading (wiping drive and re installing windows) is like amputation. Ah we'll just skip trying to fix it, and cut it off. When I was actively doing computer repair for a living I came across maybe 5 machines that I couldn't fix without formatting. Not to say that formatting wouldn't have been quicker, but it's a challenge to "actually" repair the problem instead of amputating.