Never say never... I too have not been infected in years, but then again I stay away from shady sites. But never let my guard down as any legit site I visit can be compromised and code injected with out the authors knowledge. lol
I re installed windows in the end and all has been well for the past day. Hope it stays that way! Still not sure where the Trojan came from.. but i have an idea of where it came from.
You used the term "full format / quick format" several times in the context of wiping the mbr, so I am not sure what you mean.
^Yes, by way of habit I refer to a Low Level Format as Full Format. I assumed post #13 explained things, as Sykosis pointed out... sorry for any confusion.