Yes if you bought the CD or the Download you can install it on 5 computers. Download it the same way as the first time. Where did you buy it from?
How to download your purchase
https://ttlc.intuit.com/community/installing/help/how-do-i-download-the-software-i-purchased-at-turb...
Access your downloads here
https://shop.turbotax.intuit.com/commerce/account/secure/login.jsp?pagecontext=download
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). Enter some basic information, then go to the state tab and download the state program. Then try to open your existing return, go to FILE - OPEN
