If you used the Desktop CD/Download program for 2019 you will need to have the tax return file ending in .tax2019 from the old computer to open in the program to amend. It would only be saved on that computer and any backups you made. Do you have that file?
If you don't have the file you will first have to recreate your original return. Then when it matches each line that you really filed you have to tell Turbo Tax you will mail it so it thinks it was filed. Then you can amend it.
