Thank ****, I finally solved this, after hours and hours of headache!
System restore does not work.
What you need to do is boot up from your Windows 7 installation disk, go into the "repair" section, and get into a command prompt. Then navigate into your c:/windows/system32 directory (for some reason my C drive was referred to as the D drive in here, ie d:/windows/system32), and replace the .dll files you put there with the original ones (hopefully you kept a copy).
All back to normal now