If I understand you correctly, you renewed before your expiry date? If that is the case,your Renewal should automatically resume when the previous Subscription expires. Or is this presumeably for another computer?
To further answer your question in these regards, Customer Service and other types of support can be reached by the following links...
McAfee Volunteer Moderator
Moved to "My Account Online" as a better spot. If you didn't uninstall the software first before resetting, then 1 license will still be showing as used. Go to your account page and see if you have a spare one available, if so then use that but I would phone Customer Service , or use the online chat, both free of charge, and explain the situation and they should then free up that license for you.
Change Country at top right if necessary.
I have checked the records and found that your Subscription is valid. You can login to McAfee home using the link home.mcafee.com and download the Product from My Account dashboard. If you are re-installing on the same PC then there is no need to Deactivate your old License.
Post back for clarifications..!
I reinstalled mcafee on the same PC but now I used 2 of 3 licenses. I could not reactivate the old license. Thank you for your help and your kindness.
Customer Service can adjust the number upwards again to compensate if necessary. Just ask them.
By any means have you Renamed the old PC with a different one. If so you need to login to McAfee home and "Deactivate" the PC with "OLD NAME". By doing so you can gain the unused License.
Please take caution while doing this and double check the computer name wherein McAfee is currently installed.