Both companies have designed laptops that only work with hardware pre-approved by HP or IBM. In other words, if you buy a new wireless card for your laptop, the computer may inform you that the card is not approved. There is no technical reason for this restriction: it is certainly not in the interests of the customer.
Both companies have been engaging in similar practices with printers (and I’m sure they’re not the only ones). Lexmark (an IBM subsidiary) recently sued a company that made replacement ink jet cartridges, claiming that this constituted a copyright violation. The court sensibly disagreed. HP, meanwhile, has designed region-coded printer cartridges: a cartridge from North America will not work with a printer from Europe.
HP and IBM certainly aren’t the only guilty parties: all DVD players have built-in region coding, as do video game machines. This is why I didn’t buy a DVD player until 2003, and why I don’t plan to buy a video game machine any time soon. Automakers have diagnostic equipment which deliberately locks out competing repair shops; it’s only a matter of time before they try to exclude competing parts too. The truth is, big companies love monopolies and hate the free market. They only play fair when we force them to.
Update 2005–03-03: The title used to be “HP and IBM are Evil”. Reading of genuine evil in the world, I think this is an abuse of the word. Besides, “sucks” is the accepted term for bad corporate behavior online.