Fair enough. You have plan this out right( and I have just as many auths as the next guy) but I can still build a new box from scratch and be up an running in it in 4 hours on a Saturday. If it takes a week - there’s a problem somewhere.
Another real time waster is thinking you have to reinstall sample libraries etc that could literally take hours or days. I stopped doing that years ago and now keep the same sample hard drive in place for all my builds - even when moving to new hardware - so that shaves massive time off the clock.
Well - since most auths are based on heavy duty security hashes using hardware component IDs, software IDS and hard disk IDS - transfer would be impossible.
PLUS there is no way to do an “in-place” upgrade of Windows XP-> Windows 7 - so you will have to bite the bullet and start fresh anyway. If it were me - I would have another more modern PC on hand and install to that…and leave the old one as a backup unit or secondary.