1. Boot into the System Recovery Options screen.
2. Click on the Command option.
Then type in sfc /scannow then press enter, like this:
I do not have CI.dll on my system, I have ci.dll. That is why I suggested the download (you will need access to another pc , of course )
You place a cdr in the cd/dvd drive - do not format it, if Autoplay pops up, just close it.
Then rt click and run as admin on the .exe you downloaded
click Run , and Ok the uac prompt. Then click burn.
You now have a bootable cd to boot into your pc and find and hopefully remove any Trojans, etc.
Hope it helps