I know the jungle of PCs has some strange beasts in it, but I still suspect that there is a very strong Pareto curve, even considering the kinds of PCs that the stereotypical retired parents have. If Ubuntu (say) decided that they were going to release a version for Windows refugees,they could probably mop up 75% of the market by focusing on Dell hardware and Logitech peripherals, and get to 80+ with HP and whoever the number 3 vendor was. Leave the 2005-era Packard Bell junk to Windows, define the base level, and partner officially with these vendors to get access to their build sheets and specs to deliver a solid path out of Windows. It could be done. (It wont be done, though, cos theres no money in it)