The problem with Windows is the whole thing is too damn big... every time they release a new OS, it has to run on all the legacy hardware, and run all the old Windows apps. Did you know most Win 3.0 stuff from 16 odd years ago will still run on Vista if the original software was written using supported APIs?
Time to take a lesson from "Uncle Steve" and cut the cord, I says... at least say no to anything pre-Windows 2000, software wise... look at Apple; they've even managed to tell graphic designers, one of their biggest niche markets, that they'll have to buy now-obsolete G5 machines if they want a new Mac that will run Photoshop before the second half of 2007... that's ballsy!