On the screen with the heading "Enter major purchases" you entered the item type, description, cost, and sales tax. When you click Continue on that screen, what is the next screen that you get?
Are you using TurboTax Online or the TurboTax Desktop software? If you are using the desktop software, is it in Windows or on a Mac? What version are you using (Deluxe, Premier, etc.)? If you are using the desktop software, make sure you have the most recent updates.
