Tried that, it's giving me the "Login Failed" dialogue. So, no go.
Okay, then it sounds like you have an issue many of us older players had when the site was revamped. That being the use of the same email address for more than one account.
What you will need to do in this case is contact support relaying this information. Since it's been a while since you played, you will probably have to register a support account.
Go to
US Support and click the register link on the right side. Be sure to use the same email address linked to your ingame account. Follow the instructions and give support a detailed reference to your issue.
If it's the case that you have more than one account tied to same email address, while you are waiting for support to get back to you. You should probably ensure you have a new email address handy for them. As they will ask you for a new email address to tie to any other accounts linked.
Hope this helps
EDIT: just saw your own edit and still think what I laid out is your issue. So I would go ahead and contact support.