So, was it nothing but a Trojan? At least that's what I got with my crappy english. 
Anyways, could you guys help me?
You see, I also have a "mysterious file" >registryboosterplc<, and everytime I attempt to delete it I get a message telling me that is either used by another person or a program, so what could it be? The last that I remember is that I was running an "online virus scanning", and I accidentally cancelled it out of a sudden, and then I got that file in my deskop, wich has an "blank window" icon and can't be even activated because is not a "valid application", pretty much like most unfinished downloaded files, but It can't be deleted for the later reasons.
So, what can I do? Is there a way to restore my the system checking of "Ctrl+Alt+Delete"? For some reason, It only displays the status of the user, and it would help if I could actually see if there's actually a program using said "annoying file", or anything out of the ordinary for that matter.