There's a new ransomware scam that is very nasty called Cryptolocker. It
encrypts your files and you HAVE to pay to get them unencrypted, there
is no cure currently and probably unlikely to be one given the nature of
this one. It has only been in the wild for a few days and I have already
had a few emails with it attached sent to my honeypot address. The most
important thing is to ensure you have backups of your files and are
vigilant. It appears to trigger from emails with a Zip file attachment
at the moment. That could change.
The variants are asking for between US$100 to $300 currently.