I'm so glad I backed up my sharepoint site.
When it's time to choose how you want to perform the upgrade, my advise would be choose the parallel option not the upgrade everything choice. I've never seen an upgrade break something so completely, and it was a generic site too. As I said I'm glad I backed up my site. But beware, restoring your site will be a challenge because of components left over from the upgrade. I needed to re-install IIS as well as SharePoint.