Thank you very much, essexboy.
I have done all you say in your last post. Only I had a little problem to remove Combofix. First time I have tryed to do it, it has started a new scan...
I let it finish and then I tryed it again. It started a new scan again but I stopped it with Task Manager and then it shows a message: ComboFix is uninstalled. I hope all was right.
I'll download and install the others programs you say and I'll try to keep clean.