You have taken the plunge and bought Lightroom 5. In the video below, I show you how to upgrade. I discuss how you can find your old catalog if necessary, how to ensure that your new Lightroom 5 catalog is named appropriately and that your presets come along, and how to remove your old catalog and software.
This video has been UPDATED to include the scenario where Lightroom does not prompt you to upgrade your old catalog.
For higher quality video, hit Play, then click on the sprocket wheel in the bottom right and choose 720/HD.
(For those of you more experienced users wondering why in this video I have users who store their presets with their catalog rename their catalog later, it is because if you do it in the upgrade dialog, it will put the catalog in a new folder, which will separate your presets (i.e. your Lightroom Settings folder) from this new catalog. If you choose to go this route, copy your Lightroom Settings folder into this new catalog folder.)