I will tell the story how I lost 0.4 BTC.
First of all sorry for your loss mate. Thats a really big amount for most of the average working people.
It is (was) a paper wallet I generated in bitaddress.org. I generated it online, in my work
Thats the problem. If you generated it online, you cant say it as a paper wallet. Its an online web-wallet and your keys can be stolen if you have trojen/malware in your pc, as simple as that. Please beware next time, amd clean your PC.