The following article from Arstechnica discusses a malware that is becoming more prevalent, and which wipes all the data files on your computer. Ars can't tell where it's coming from, or even why someone is doing this, and there's no apparent solution except be careful on what you click. Another option is to do a complete backup of your computer to an external hard drive, or perhaps the 'cloud', so you could recover your files if ever you got infected.
Just passing this on FYI and something to be aware of. The article doesn't mention whether an AV program, such as Avast, et al, would be effective in blocking this malware. Right now, the article is just more of a 'heads up' alert..
Jim Hamm