I assume you used the Desktop program? Sorry if you didn't make a backup of the .tax2021 file it is gone. It is only on that computer. Is the hard drive crashed? Maybe you can take it out and put it in an external enclosure to access from another computer.
You need to install the program on the new computer. Do you have the CD or download?
This probably won't help if you don't have the tax file.
After you get the program installed the first thing to do before you open your tax return is to update the program and install any state programs you had. Then open your file. So you first might need to start a fake return to be able to download the state program (go to File-New Tax Return).
Then go to FILE -Open and find your return.
See this article on how to move your tax return to another computer…….
https://ttlc.intuit.com/community/tax-data-file/help/how-do-i-move-my-tax-data-file-to-another-compu...
