Did you encrypt your wallet with password?
Next time don't use Windows. Use Mac OS X or GNU/Linux. If you store large amount of bitcoin, you may use cold storage / paper wallet.
Was you using windows without an outbound firewall? (Windows firewall does not block Outbound connections and any undetected key-logger would send everything to the hacker without you even knowing)
the wallet had passphrase encryption. Not sure about the firewall. Kasperski and AVG were on and nether triggered. ran Malwarebytes.org scan and it did flag a bunch of stuff that the AV programs missed. Certainly learned a lesson about importance of paper wallets.
this character has posted to this community in the past. I am hopeful moderators can DOXX him and hopefully together we can shame/coerce the guy to return the coins.
Sorry to hear about the lost coins.
Why are you running kaspersky and avg at the same time though? You shouldn't be running 2 antivirus's like that at the same time.
Often times they can negate each other. Then neither one is effective at catching anything. Just run kaspersky, make sure it is up to date and run a full scan.
You can also try running adwcleaner
http://www.bleepingcomputer.com/download/adwcleaner/ and combofix
http://www.bleepingcomputer.com/download/combofix/.
You should not be using the same wallet anymore until you figure out what happened on your machine(or at all really). At this point consider the machine that had the BTC stollen from compromised.
It may not be a bad idea to change passwords on any accounts you have as you may have a keylogger. Clean your computer first before changing the passwords as if you have a keylogger it will capture the new passwords too.
Hopefully you can get all of this figured out.