An account with an old address can be recovered in two ways: using the way from the Medium article or using "Recover Account" feature.
Using the first way (from the article above) you create a new extension account but then import your old wallet using one of three ways (encrypted key, private key or wallet file) which doesn't change the public address - it's imported to the new account instead. So, in the end, you have a new extension account but with the same address as before so it doesn't affect your lottery status - you are still a winner and should be able to access the ICO platform.
Using the "Recover Account" option is simpler because you fully re-create the old account without the need to first create a new account then, you can import anything additional to it. You just need to enter your old username, password, and private key backup code and you have recovered your account.