I can confirm of course you do not need to order again: as you have lifetime license, you can re-install and use it any time.
Please write an e-mail with email@example.com about some details which I can use to look up for your existing license.
For example, write your name / username used in registration, e-mail address you may used during order, approx. date of purchase.
Then I'll search and send back the license code and registration details.