Windows misbehaves

At the weekend, I was installing a software update on the ThinkPad when the Microsoft installer decided to fail for permissions reasons. It didn’t think to tell me it needed to be administrator before running through the entire install, no, that would be too easy. And somehow although it wasn’t privileged enough to install the software update, it was privileged enough to wipe out several vital system files. So Windows started demanding the Windows 2000 CD.