Hi, I'm Robert and I'll be helping you with your financial software question.
quickbooks should allow you to use the same license number with no problem.
Try doing a clean install where you delete all traces of the program ( but not the data ) as below. If that does not work please don't give me a bad rating but instead let me know exactly where you ran into a problem or the exact message on the pop up if it comes back. I think the clean install has a better than 50% chance of fixing it if you use the utility and instructions in the link below. But if it doesn't I will be happy to help you further tomorrow
QUICKBOOKS CLEAN INSTALL
try doing a clean install with the instructions on this page. It should not effect your data but i always recomend making sure that you have a good back up and / or a copy of your data file ( it ends .qbw ) in a safe place such as a flash drive or another folder.
It requires that you have a copy of the quickbooks install cd or download. If you downloaded from intuit you can get another copy free.
If you purchased from Intuit directly you can download again for 3 years.
For quickbooks go to https://www.intuit.com/login/
click on cart orders downloads
sign in with your intuit id and password. ( usually your email address is the id )
click on downloads and unlocks
That should give you a list of any intuit product that you purchased online within the last 3 years with a download button.
This page has complete instructions for the uninstall and reinstall INCLUDING a clean install utility that you want to download and run.