Windows XP and System Upgrades

I'm thinking about upgrading to XP and I have a question I've never got a straight answer to:

If I install XP on my current machine, and then put together a completely new machine, can I install the same copy of XP on the new machine or will the XP registration prevent this?

I want to upgrade to XP with my current machine but I'm afraid doing so will limit my machine upgrade options.

Thanks

No, you can't put it on more than one machine.

And xp won't limit you in upgrading your current rig, you just can't put your copy on a bunch of other machines.

Yeah, I'm not trying to put it on a bunch of machines, I was just checking that I could replace my current machine with a new one, and install XP on the new one and have it work. It appears this possible.

Thanks!