It's just been announced a few hours ago that CCleaner was hacked aprox. 1 month ago; anyone that has updated or installed CCleaner between then and today has been subject to malware. They said an initial 2.2million computers have been confirmed infected (mine included); they believe the total fallout will be around 20 million computers actively compromised from August - September.
You can download MalwareBytes to scan your files and get rid of it - this is what the file name looks like...
Anyone that has played guild wars or made payments via login services, I'd suggest changing your passwords promptly. The techs that developed CCleaner haven't yet released what data has been stolen.
Change your passwords to anything you have logged into such as:
Malwarebytes official link: