Seriously? And you are blaming blockchain.info for that? Firstly, how secured is your wallet. Do you have a strong password and is 2FA even enabled? Also, do you even trust the antivirus on your system or it is just one of those free antiviruses that detects nothing you are using. You should know that any loophole in your PC or browser with a malware present can easily zap all you have, so question your own security first.