Although, this question has been answered, the accepted solution may not work since there's a new variant of this ransomware which replaces explorer.exe file. To remove the virus, you need to over-write explorer.exe. If you got infected with a new variant of this virus, follow removal guide exactly as written:
Today, we found the easiest way how to remove this virus from computer. I have Windows 7.
Any anti-virus programme could not find or detect this virus in my computer (tryed Avast, Windows Defender, Malware Bytes Anti-Malware, Microsoft Essentials).
The trouble was that my original anti-virus software expired and after virus download, the new installed antivirus softwares could not work
The way how to do it:
a) safe mode (with net, or without)
b) START icon left corner
c) the bar to find programes or folders/ go to COMPUTER and use the ,,find bar" there
d) writte *.exe, click find in all folders, time or date limitation when you download the virus (I mean the exact day of download)
e) See file/s (NUMBERS).exe
9. Celebrate by doing the dougie
10.than completely scan your computer by some anti-virus and delete all viruses