Installing Windows on a Thinkpad
... required a FreeDOS boot in between: I had that Thinkpad R40 sitting in a corner, with Windows XP installation media hidden in that protected IBM recovery partition, and with no particular reason to preserve the Linux installation that sits on that machine. So I decided to push the blue "Access IBM" button and tell the machine to re-install itself to factory settings.
Interestingly, that left me with a system that still had remains of GRUB sitting in its MBR, and wouldn't boot. Amazingly, the IBM startup menu seems to offer no way to do a simple FDISK /MBR. (It also doesn't seem to offer the option to erase any existing data partitions -- such as my Linux installation.) I ended up typing that command into a FreeDOS command line interpreter; after that, Windows would boot like a charm.
Yes, the recovery mechanism is nice. But it wouldn't have been very useful in, say, a hotel room without Internet connectivity and another machine to burn that boot CD.
