I hope you're confusing something. If not i will look for new wallet. So MyEtherWallet is the most comfortable wallet for me and I use it more then half a year and still haven't any problems.
I agree. I have been using MEW since one year. Some how my private key is compromised..I just want to get better understanding how the person who hacked my account got the private key
Maybe you caught the Trojan virus. I advise you to check your computer for viruses, and even better to reinstall the operating system. Or maybe you somewhere by mistake entered a private key instead of the wallet address.