Microsoft still owns the business desktop and the multitude of application interdependencies pretty much guarantee this for a long time to come. However the desktop investment is static if not slowly declining, and what should (probably does) terrify Microsoft is that in every area our customers' spend is growing - mobile, Cloud, virtualisation, search, advertising - we've not had anyone ask about Microsoft products in years.
IRO desktop, we've been here before with Vista and Millenium being two notable disasters. But if Windows 7 turned out rubbish we'd still be promoting XP, and if they were both rubbish we'd still (probably) be promoting Windows 98. Windows 8 is never going to fly and while we do not yet know what Windows 9 will bring, we do know that regardless of official policy Microsoft will support Windows 7 for as long as most of the business establishment is using it.
IRO mobile and search, I really feel sorry for Microsoft on this one. Finally after years of producing third rate trash in these markets they finally produce an excellent OS and decent search engine - and nobody seems to care. Surface has proved that producing their own kit is no guarantee of success. Just a crummy situation for them to be in I guess - huge investment is just barely keeping them in this game, but doesn't seem to be making it in any way profitable.
IRO Cloud, the only way they will ever get real traction with new businesses is if they make the base OS (minus the GUI) free and charge only for the GUI which is still the best available (IMHO). That's just the bitter reality - entrepreneurs starting out usually have (slightly) more time than cash, and therefore just simply won't consider paying for something they can get for free and without the added hassle of licensing management. Existing businesses that succeed in moving Windows business applications to cloud are also likely to find themselves moving to Linux for their new applications as well. A free Windows Server "Express" is probably only a matter of time, but the longer they wait the less relevant Windows will be in future.