So I got everything hooked up, booted it, and promptly wound up in Activation Hell; the copy of XP installed on those hard drives was Dell OEM, and the new motherboard/CPU are most definitely not Dell. Because it's OEM, it has no activation grace period, and demanded immediate response. So I telephoned in the activation request, and got the "this is not a legitimate copy, you pirating bastard" (approximately) response as a result. Once I got past the automatic system and talked to someone in India, I Was informed that the OEM license can't be transfered, so I'm out of luck. Well, sort of out of luck; what I needed to do was a license swap. My other computer (the one that had the dead motherboard) had an off-the-shelf copy of XP; it's a Dell, and moving onto the motherboard/CPU being vacated by this set of hard drives, so it's a valid target for the OEM license, while I can use the general license on the "new" computer.
It is, of course, not anywhere near that easy. Because it's an OEM copy, it won't accept general keys. Crap.
This is Activation Hell: Windows can't activate because it has an invalid key; you have a valid key, which Windows refuses to use. You also have another operating system (Vista Ultimate), which you can't install because it has to be installed from a running, not-Safe-Mode system to do so without requiring reinstallation of everything. In short, it is impossible to activate the system within the constraints of the system, while the system is working correctly (for as "correctly" as WinActivate ever works; I'm not enamored of the implementation, although I understand its necessity- heck, I was in favor of it before I started working for Microsoft), despite having one or several legitimate licences available.
The way around this is to reinstall Windows, as an install-in-place without deleting installed applications; this works, except it proceeds to hose all my drivers, so when I get the new key entered (and it activates without my even having to explain why the activation moved), the operating system is in a questionable state, at best. It's back to IE6 (among other features) and Windows Update has somehow violently broken so nothing in my power can make it apply the 93 security patches it so desparately needed. (Incidentally, the new key- which had to be immediately activated, since the system still thought it had zero grace period- activated immediately from the automated system without needing to convince someone to allow for a key transfer. Go figure.)
There's a way out of this, of course: new f*cking operating system.
Did you know that a dual-core 3GHz (each) system with 4GB of high-speed RAM and a high-end graphics card actually runs Vista faster than it runs XP? Vista is actually capable of using the RAM and dual-core processing effectively.
Not to say I don't still want an XP system around, for the things Vista won't work with. Unfortunately, the computer that died lost more than its motherboard; one of its hard drives developed a physical failure, as well. Not a critical one, just a few dead sectors, but nothing Windows can boot with; the data is basically hosed. Which is exactly what I own a Windows Home Server for; the computer ran Ubuntu for a couple of evenings off a LiveCD just to have it doing something, but after confirming that the hard drive was only kinda broken, I've gone ahead and started a full restore. Nightly backups rock.
So that computer is cheerfully rebuilding itself, and the other computer is sufficiently high-spec that Vista can actually run screamingly well on it- all our various high-end games are running better than ever before. And it only takes having a computer at least twice as powerful in all respects. Yay?