Do you have MetaMask installed and have you ever connected and accessed your account using MetaMask? I a guessing you are talking about MyEtherWallet as it is one of the most widely used wallets for ETH and other tokens.
if you are using myetherwallet there are a lot of scammers around....
try to google "myetherwallet scam" and you will understand what i'm talking about!
the first i found:
https://steemit.com/ethereum/@dhumphrey/scam-warning-fake-myetherwallet-phishing-sitetake a look at this link:
https://www.myetherawllet.comare you sure you never used one like this?