Second, this is counting what are being sold the last quarter and ignoring install base and the increasingly longer upgrade cycle of PCs.
For a better picture of install base and actual usage, see http://gs.statcounter.com/#mobile_vs_desktop-ww-monthly-2011...
The entire mobile devices are at ~15%.
Third, this is Goldman Sachs, they might be shorting Microsoft stock now and will buy and upgrade it later just like they bought millions of shares of Nokia when they downgraded it and then the stock more than doubled recently, and GS made tens of millions at the least. Read the very interesting article below showing GS not following their own advice and doing a reverse dump and pump.
http://seekingalpha.com/article/1023231-goldman-sachs-and-mo...
Then we have the Register writing flamebait articles with linkbait headlines, completing the circle of worthless blogspam flamebait junk.