TurboTax CD/Download file extensions are *.TT, plus the tax year. For example, your 2014 files will all be named something.TT14 and your 2013 files will be something.TT13.
1. Find all of these files on your old computer. TurboTax CD/Download typically saves your TurboTax files to your Documents folder in folder named with the applicable tax year.
2. Plug you flash drive into your old computer
3. From Windows explorer, drag or copy all your *.TT* files from your old computer to your flash drive
4. Plug your flash drive into your new computer and transfer the files to your new computer
Note: If you want to open these prior year files on your new computer, you'll need to install TurboTax CD/Download on your new computer for those particular tax years. Those older files won't open in TurboTax for tax year 2016.