The best way to go about this?

[inspiration100]

I have been using an expired 3.8 license that had an old 4.0 version when updates stopped. I recently purchased a 4.0 suite license and I want to upgrade my forum from 4.0.7 to my new publishing suite. What is the best way to upgrade my forum?

Do I delete the old files, add the database, and then install the new license?
Do I somehow upgrade the old license (even though it's different vbulletin number?)
Will my old layout work for vbulletin suite (the blog and all)?

Thanks for the help!