Windows operating system has a utility called system restore that allows you to restore your computer to a previous day and time.
The only thing most users do not know, in the event that your system becomes infected, chances are the system restore files are infected as well. The latest malware infections that claim that your system is vunerable, and you must protect it, can be hidden on your system for an extended period of time. To just restore the system to an earlier day and time will not remove the infection. It will more times then not be restored along with all the other files. Your best bet is to have a Tech Expert remove the infection.