The games are 16-bit. Only 32 bit versions of Windows has support for 16 bit apps. 64 bit Windows run 64 bit apps natively and runs 32 bit app under emulation. 32 bit Windows run 32 bit apps and runs 16 bit apps under emulation. As such, only 32 bit of Windows XP can run these games. Windows XP x64 cannot run these. But since almost no one has XP 64-bit, this wasn't an issue. By the time of Windows 7, most PCs were 64-bit, and thus people were unable to play these games. Most people incorrectly assume that Windows 7, vista., etc can't play the games, whereas, in fact it's their 64-bit architecture that's the holdup.