Old versions cannot log in any more. You need the latest version from: ⬇ Download CIU
If you are using the same laptop as you were previously, then upgrading to the latest version is all you need to do. If it’s a different laptop, then you’ll also need to copy your progress from your backup (as @VerMishelb explained).
Once you manage to log in and you see your old progress, only then should you add an e-mail to your account to keep it secure .
Note: if you haven’t logged in the past 12 months, then it’s possible/probable that your account has been deleted. In that case your progress will be lost forever.