Cloning Windows 7

I have three PC's, all with different hardware configurations, mobo, CPU. One is running XP Pro 32-bit, one is running XP Pro x64, one is new but I have an unused XP Home licence that I can use to qualify for upgrade on Windows 7.

I have just bought the Windows 7 Family Pack, and have a few questions.

1. Given everything I've read about potential problems doing the clean install with an Upgrade licence, is it technically (and legally) possible to install the second and third PCs by cloning, once I've done the first? I'll be starting with the XP x64. If so, what would be the best time to do the cloning - before or after activation?

2. Generally, does anyone know if a reinstall is needed after a major hardware upgrade (mobo/CPU)? Regardless of the answer to the first question, I'll be cloning the clean install so that I can use it in the future and avoid going through the installation hassle again - but would it work if the hardware has changed significantly?

3. Does Windows 7 have a "deactivate" option, if you want to move the licence from one PC to another? (Like Adobe CS4?)

Thanks in advance

Reinstalls are advisable with a motherboard replacement, but not for a CPU change. There are online guides to try to help you avoid reinstalling if you change boards, but most people just plan on reinstalling Windows with any mobo swap. Hard drives, CPUs, DVD drives, monitors, graphics cards, sound cards, and power supplies typically don't pose such a problem.

You may have to reactivate after major hardware changes, although I can't recall ever having to do so personally.

Thanks for the advice!