not sure what you mean with host migration.
Anyway the game runs fine for me on windows 7 and sli and i7 so I doubt you’re pc is ‘too advanced’
As for installing, get the main game (the installer is 257mb if I remember correctly), then install then 2.60 patch.
Once that is installed install the 2.60b patch (latest version)
The main installer and the 2.60 patch are simple .exe files. The 2.60b is a zip, you need to copy the files ET.exe and ETDED.exe to your installation path, which will overwrite the ones placed by the 2.60 patch.
You can’t update straight from 2.55 (original game) to 2.60b or you will get kicked when you try to play online.
PB is kind of a mess atm, but one thing you should try and do is get an etkey.
Once you’ve started up the game you can achieve this by typing /pb_cdkeyreg in the console.
This should send a request for an etkey.
See how far that get’s you.
As for where you can get those files www.wolfmap.de is a good source.