Despite extensive internet research, I have not seen anyone answer this question. I'm definitely no computer expert so maybe I'm just missing something but...here goes.
Say my computer is infected and I want to be absolutely positive I've removed the malware. So, I decide to reformat all internal drive partitions and reinstall Windows completely, using an SD card I created when I first got the computer as installation media.
How can this be done without the virus potentially (automatically) transferring to, and then returning from the installation media itself?
Every guide I've read instructs that the reformatting be accomplished via the new installation media (e.g. using Windows Setup). This does make sense to me, because I suppose you can't format using only the internal hard drive, being as all the software there will be wiped out, leaving nothing left to "do" the formatting.
But here's what I don't get: being as the installation media will thus necessarily be inserted prior to formatting, couldn't the virus immediately spread automatically from the computer to the installation media, and then spread right back to the computer after formatting, thus making reformatting useless for removing automatically spreading viruses?! I thought reformatting was a guaranteed last resort.