A full drive format would remove anything on that drive.
If you backup online da nas will snoop ur filez.
What Oaky said, but also wanted to add:
Ransomware is a terrible thing (I know because sadly I work tech support, so lately this shit has popped up everywhere) and it really sucks that there really is nothing that can be done save pay them to get your shit back. As someone who gets a million calls a day about people losing shit to viruses, dead hard drives, and whatever other garbage..back your shit up. It is so easy now, there are even programs like carbonite that do it for you automatically (for a charge of course.)
There is no known way to get your shit back save paying them, take it from someone who (sadly) works in the industry of trying to fix people's fuck ups. The only protection against it is not to get it. The common sense should apply here though: Don't click on suspicious links, don't download attachments unless you are 100% positive what they are, be wary of clicking on recommended results on google, and be wary of clicking ads on any site in general.