I had a similar situation just happen where I went to open up an existing return I had been working and it said I needed to enter the 16 character license. Up until now it just opened fine. Like you, I threw out the box last week because I got tired of the disk sitting on my desk; so no license code. I called the help line and was on hold and then got a person who said they could see I had purchased it and would refund me the amount and I could go and re-purchase and download. I would get a new application and license. I asked if it would load my data file and he couldn't guarantee it.
While online I logged into my Intuit account and started poking around. I clicked on "Products and Billing". I saw Your Products and the version I had purchased from Costco. So I clicked on it and then scrolled down to "Licenses and Downloads". It had my license code that I copied and pasted into my TurboTax space that was looking for it and it opened up.
Don't know if this will work for others, but it saved me the uncertainty that getting a new version and avoiding an issue of loading the data files.
