Sounds like some form of malware. It's a pity you can't remember the name of that executable, as it may have given us some pointers as to the cause of your problem.
I'm going to ask one of our security experts to have a look - when she replies, follow her instructions to the letter.
If you find yourself spending days trying to get it resolved, I'd probably consider wiping the drive after backing up my data and then doing a clean install. That's always a last resort, but a clean fresh install takes me two hours...so it will lead me to a resolution faster than spending days hoping for one.
Takes time though... Ama try after I scan.