I think you need to understand the problem to find protection.
A VPN will encrypt your traffic on the Internet so that others can't see it. In itself this won't add much protection at all. Your browser still needs to be updated, you still need antivirus, you will still use antispyware.
Really, the VPN will slow down your conncetion but unless you have someone looking specifically at your traffic, nothing changes much.
One case where a VPN is a good idea is when connecting to the Internet on a network you have no control. For example a WiFi service. Once you connect other people might be "listening" and if for example you don't use a secure connection to a service such as Facebook then, potentially, the cookies associated with your session could be used by someone else to impersonate you.
But at home or at work, a VPN would just add an extra layer that won't protect you.