Ok, now that I have a PC which isn't literally over 10 years out of date, I can finally start playing FFXI on my PC instead of my ancient PS2.

I know I can just login to my account on the PC, but how do I get the software first? Do I need to re-purchase it on PC somehow? (Especially if I want it registered on my Steam account) or is there a way to login and have it download the software since I already have an account?