This is a very dangerous malware program as well. It has the ability to encrypt your data with no easy way of getting it back. I definitely don’t recommend paying the ransom, and trusting they’ll provide the decryption key. Instead, backup your data often, but keep your backup device disconnected when you aren’t backing up. This malware can also encrypt backup devices and even content on network connected drives.
There’s no easy way to decrypt the data or restore it once it has been encrypted, so trying to do so may prove to be a fruitless endeavor. I suspect this kind of malware is often installed through “drive by” attacks, so make sure to avoid clicking on advertising and other links that may be suspicious. Be careful of e-mail attachments and other kinds of communications with web links or file downloads.
If you are suspicious about an attachment you can use a program like MalwareBytes to scan it and ensure it’s safe. It’s best, however, to avoid them altogether whenever possible. This form of malware will likely become more popular as different variants of it are released in to the wild, so please ensure you have up-to-date anti-virus software, a secure Internet browser (i.e. Google Chrome) with plugins that block advertising (AdBlock) and give reputation ratings of web sites (Web of Trust). And install your Windows updates whenever important ones arise, rather than relying on the automatic update system. The sooner they are in the sooner security bugs can be fixed on your PC.