Do a search on this forum and use the words "moving subscriptions" and you should find your answer.
(DISCLAIMER: I am NOT an employee of LMI, nor do I have any financial concern in LMI. I am strictly a HAPPY USER of LMI products. I am using PC version and XP SP2. Other systems or versions may act different than described above.)
You can log into your account from any computer and then look at the top left area of the page. From the My Computers page, click Edit for the PC you want to remove and you can delete it. Afterwards, click on the Installation Links and setup a link to install ITR onto another PC.