As far as your question goes, there is a simple explanation. You WILL notice that your PC is infected next time you'll try to use it. So, you will have to "truck" every thing since last time you shut down your PC, which can be a year back.
By removing every thing since that day, you may "accidentally" delete something useful, but the thing is that MS Windows became very stubborn to die these days, so the system will "restore" itself and put all the accidentally deleted files and entries back to were they were, also you can always reinstall some software if you see something fishy going on with it. It is much simpler than peepel think it is, it is just takes a little effort on you part and knowledge (from sites like this)
PS: I would just copy and paste the thing, but after seing so much "log" manuscripts was thinking about keeping this site's server lighter load.