Hey again, mate.
1. It should have no trouble with a 2TB drive.
2. I'm a bit confused by the 4th point. If you say "buy Windows 7 again" do you mean that you already own a retail copy of Wndows 7? If this is the case, then you can just make a fresh install of Windows on the new drive and then connect the old one externally either via a SATA to USB cable, an external enclosure, or a docking station, so that you can transfer your personal data (videos, pictures, movies etc.) to the new drive. After that, if you decide that you want a caddy for the old drive - wipe it clean and reformat it (after you've transferred your personal data), then connect it to the caddy so that you can use it as secondary storage.
3. If you do not own a retail copy of Windows, then you'd have to clone your drive to the new one. Here's a link with tips on how to do that: http://www.howtogeek.com/199068/how-to-upgrade-your-existing-hard-drive-in-under-an-hour/
Cheers,
Boogieman_WD