Or, how things can go wrong in the ways one least expects.
I needed a replacement PC shipped here ten or so days ago. Fedex are pretty good at shipping things fast. A quick email back to the office in the US and it was despatched the same day. A public holiday here in the Philippines slowed us down a tad but it arrived; dead! The 3.3 Volt rail was dead.
Ok, let's take the power supply out of the old PC and put it in the new. No go! The old power supply was ATX, the new one was AT. If you know much about PC Power supplies you're shaking your head in disbelief. How is it possible that the old supply is ATX and the new one is AT? I don't know either. All I know is that that's how it was.
So if you don't know, here's why. An AT power supply has a power switch between the mains and the supply itself. The power switch on the PC is a mains voltage power switch. An ATX power supply is 'always on' in the sense that there's no break between the mains and the supply. Instead, the supply provides a low power 'sense' circuit. When it senses that power is wanted to be turned on, it turns on. Likewise, when it senses that power is no longer wanted, it turns itself off. AT is old - it dates back to 1984. ATX is much more recent; I think from about 1997.
The power supplies have different connectors to the motherboard but that was the least of my problems. The motherboard in question has both. What was a real show-stopper was the front panel power switch. Totally incompatible!
So I requested a second replacement. I had other things to do in the meantime. The second PC arrived today. This one worked, to the extent that it could boot. But it's running Windows XP and it hadn't been activated. You get 30 days from installation to activation; after that period you cannot log on to the PC without activating.
These PC's were delivered to us more than 60 days ago. You can see where this is going. For whatever reason (I suspect contractual with Microsoft) our supplier ships us PC's that haven't been activated.
Our supplier also ships them installed with the default configuration; this makes sense; I wouldn't want to try and guess the wierd and wonderful requirements of some random customer. Thus, they come setup for DHCP. Our office network back in Phoenix uses DHCP so no problem; the 'new' PC can connect to our network and make it out onto the internet to validate. Alas, our customers network doesn't use DHCP; they use static IP addresses.
So I now have a PC needing validation before I can log on. But I can't validate until I can log on and set the static IP address. But I can't log on and set the IP address until I've validated. Infinite loop!
Fortunately the PC was shipped with the original XP SP2 media and the Certificate of Authenticity (COA) so I spent the hour needed to blow the original installation away and reinstall. From there it was a breeze.
Now I want to stress that I blame no one for this. I'm here at the pointy end and I didn't anticipate this problem. It's just one more step we need to put in place before we ship. Bring the sucker up on the network and validate it before we ship. Let's add another checkbox to the list.