Could be Matrix. Sadly I couldn't find a decrypter for the infection. There possibly will be one available in the future, so you could try to create a backup for later. Most important thing is to not run your infected Windows anymore. My advice would be to get an external HD for backup and boot a free backup software from CD or USB. Get a bootable antivirus, boot from that and clean your system. Now comes the hard part: Wait until someone releases a decrypter.