If you use the CD or download TurboTax software, your tax files are stored wherever you save them on the computer that you use. In Windows the default location is the My Documents\TurboTax folder, but you could have saved them somewhere else. The tax returns data files for 2017 have the file name extension .tax2017. You might also have saved your tax return as a PDF.
You will want to copy your tax files to the new computer. You can copy them from the old computer to the new one before you discard the old computer. You can copy them to removable media such as a flash drive, CD, or external hard drive, or you can copy them to online ("cloud") storage such as Dropbox, then copy them to the new computer. Even when you are not changing computers, you should make backup copies of your tax files on external media in case of any problem with your computer. TurboTax does not have copies of your tax files when you use the CD or download software. The files are only on your own computer and any backup copies that you make.
