WRT your first point, Microsoft used to sell Windows on multiple architectures. They abandoned Alpha, PowerPC, and MIPS in 1999. http://en.wikipedia.org/wiki/Windows_NT#Supported_platforms A big part of the problem was that software vendors did not make non-x86 versions of their software and subsequently users were confused and disappointed that the software that they wanted to run on their (e.g. Alpha) computer either wouldn't run or had to run in an emulator and thus ran slower than on an x86 machine.
Microsoft supports two architectures currently: x86/Itanium and ARM with WinCE/WinMobile/WP7. There is no real synergy between the two currently, e.g. the "Office" apps that run on ARM are totally different beasts than what run on x86. The primary crossover is "mindshare" - i.e. users recognize the names.
Microsoft supports two architectures currently: x86/Itanium and ARM with WinCE/WinMobile/WP7. There is no real synergy between the two currently, e.g. the "Office" apps that run on ARM are totally different beasts than what run on x86. The primary crossover is "mindshare" - i.e. users recognize the names.