FYI. There is a new type of ransom attack surfaced recently, but instead of locking you out until you pay up, this new one encrypts your files, you only get the key after contacting the given mail address and pay up.
If you come across the name Koeserg, avoid.
Malware investigators have only recently found a fix for it.
If needed download and run this tool
(you don't have to use ftp to download it, you get the option)
I don't see any purpose in downloading and running just in case, you will be in no doubt if your PC is infected.