This video may prove useful. It uses Kaspersky rescue Disk 10:
http://www.youtube.com/watch?v=5Ws2IcM4CMA
If the video didn't help, the following procedure also uses Kaspersky Rescue Disk 10, then employs the WindowsUnlocker feature.
There are simpler fixes for SOME of the ransomware infections, but this should work with all forms of ransomware...even those that disable all Safe Mode options, plus Regedit and Task Manager, etc....
Use a working computer to download and burn the Kaspersky Rescue Disk 10 .ISO file. Burn the file to a CD or DVD or flash drive, then use it to boot your infected computer. Once at the desktop, use the WindowsUnlocker feature.
This link is for the download of Kaspersky Rescue Disk 10. It's primarily designed to boot and disinfect computers that have been rendered unbootable due to an infection, but it's fine to use it on an uninfected machine. The .ISO file is 262MB in size, and it's easier to burn it to a CD or DVD than a flash drive, but the link does includes instructions on how to burn the file to a flash drive (USB device):
http://support.kaspersky.com/viruses/rescuedisk
If you don't have burning software installed on the working computer, download and install Ashampoo Burning Studio 6. It's free, and I recommend it...I use it myself:
https://www.ashampoo.com/uk/gbp/pin/0710/0-Offline/Ashampoo-Burning-Studio-6
Start up Ashampoo and select Create/Burn Disc Images...then select Burn a CD/DVD/Blu-ray Disc from a Disc Image.
Burn the CD or DVD, and use it to boot your faulty computer. You may need to enter your BIOS (Setup), and change the boot sequence to boot from CD first, but this isn't always necessary.
As already stated...once the CD or DVD or flash drive has got you to a desktop, select the WindowsUnlocker feature. Once your computer is unlocked, scan it with your currently installed security product, or download a free one.
It should be noted that although certain ransomware pretends to encrypt some files, at least one example (West Yorkshire Police) actually does encrypt some files. In this case, you should use a decryptor utility supplied by Kaspersky Lab.
This video shows how to remove the West Yorkshire Police ransomware:
http://www.youtube.com/watch?v=1gwMhaJHwro
This link leads to the RannohDecryptor utility, from Kaspersky Lab:
http://support.kaspersky.com/faq/?qid=208286527
This WindowsUnlocker explanation and video link should also prove useful:
http://support.kaspersky.com/faq/?qid=208285998
http://www.youtube.com/watch?v=C5hvSlrOUlE
Hope this helps.