You only need a trusted antivirus with an internet security like Kaspersky for you to not be infected by the copy paste virus. If I were you, I wouldn't recommend Microsoft Security Essentials because it is still prone to other virus that steals cryptocurrencies. I also see no need to discuss this further because we already have the easiest way to be safe from that type of virus. Either way, thanks for this informative post.
Regarding Kapersky,
the US government doesn't seem to like them. I'm not saying they're bad or that the allegations against them are true, but it's a factor you may want to consider before using their antivirus.
Either way, the best way to deal with these viruses is to not deal with them at all. If you're running Windows, it's very easy (and free!) to dual boot Linux, which you could use exclusively for crypto activities. Most popular wallets support it, so you won't run into any compatibility issues, and you're far less likely to encounter any malicious viruses in the wild.