I have been growing with Windows, from Windows 3.1, which I had on my first personal computer back in the '93. To me it meant the computer itself. And didn't even know what the Microsoft Corporation was. Windows was the name and the logo, and Internet Explorer, Word and Excel elements of it, part of my PC.
Growing, I followed all the new release of this OS, rather buying it, till I have started buying laptop in which those software are sold in a bundle. I didn't gave to MSFT a lot of money compared to +17years of heavy usage.
As me many of my friends acted. On eMule I always found what i was looking for, each new Software releases was and is at my disposal just days after the launch. I have also tried Ubuntu 9.10 as a OS and found it interesting, but not so simple. I have read very good thing on the release 10, more user friendly. That is the Windows strong point.
So even with the Windows Genuine Advantage i don’t think the normal user’s market will be so profitable for the Corporation. Microsoft Windows for Corporate for sure is different, it has been profitable.

Maybe Office is different. I will later on my career be able to pay for the Office Packet, which competitors like Open office are not ready to substitute in my dream software’s portfolio, so far. Office it’s a must, but still its costs over 200€, too much for a student paying for it.
I’m nicely using right now Office 2010 in Beta release for free, and I’m very happy about it. It has all the good things that the 2007 propose, plus something new like outlook aligned graphically to others software.

I think that the main market and profit for Microsoft will come on the Office Packet, but I haven’t done any research as Prof Dans said. We’ll see if tomorrow I will change my mind.