Please restart the computer into Safe Mode by continuously pressing the F8 key after the boot sequence. Before doing this, please download GMER. It's an anti-rootkit utility with the ability to scan the files and kernel pages.
Once you are in Safe Mode, start GMER and perfom a scan of your files using the Scan button. You will need to delete all the red items that you find. Right click them and choose Delete for all the entries available. After you finish this process, restart the computer and the ransomware will stop from loading. Then you can use your favorite antivirus solution to clean the remaining items, if there are any.