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.
![Stick Out Tongue](images/smilies/tongue.png)
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.