Please, can You help me about CoD?

[Seeker]

3 is possible, it'll be annoying, but possible.

Here's how:

1. Buy the downloadable version via Steam.
2. Steam allows you to install and play from multiple computers (just not at the same time), so install it on the office machine too.
3. Update the office machine.
4. Copy the entire game onto a USB key. A 60 Gb USB key isn't much these days.
5. Over write the home machine with the contents of the USB key.

In time, I think you'll see this will be too annoying, and that you'd be better off patching at home, even if it takes all day to download while you're at work. Steam alloes downloads to resume, and to be honest, it seems quite a reliable and unobtrusive service.