Hi Thanks for your advice. What you can see in the photogrph is exactly what Ive got on my screen. Its not possible to boot into Safe Mode and the only way Ive got into the machine at all is to boot up from a USB stick - http://www.pendrivelinux.com/yumi-multiboot-usb-creator/ There are various tools you can run from the YUMI multiboot, including the Kaspersky rescue disk and various antivirus programmes, but none of these are able to get going on my machine and trying just results in various error messages. I think unless I can track down an unlock code on the web I'll have to get the machine wiped. Do you have an advice on this process bearing in mind I cant access the machine other than via the USB multiboot? Are you aware if this specific of ransomwear has a name? Any searches Ive done for unlock codes have failed to turn up anyone who has had exactly the same problem and hence Ive not managed to find a code so far. Thanks again