There is this new nasty virus going around in emails that holds you ransom.
It is called Cryptolocker.
Basically it disguises itself as a .pdf but really it is an .exe. When opened it will encrypt your files and create a public and private key. A ransom is then sent to pay anywhere between $100 and $700 and if not paid the keys are destroyed and you therefore cannot access your files.
Beware as this is a very dangerous virus once it is executed on the machine.
I work in IT support and this is something we need to take into account not only for our network but also for home users which is why I am informing everyone here.
Read more about it here:
http://krebsonsecurity.com/2013/11/h...er-ransomware/