This 'appeared' on a clients computer. It's the usual variety of ransomware, but I'm finding it very difficult to shift. System Restore fails (on three different restore points). It doesn't show in Programs and Features. MBAM and Hitman pro have found various bits of malware, but this thing still reappears on boot.
I've been able to stop it by removing it from the startup list in CCleaner, but would prefer a more permanent solution.