Windows XP is in its death throes, or at least that is how Microsoft would like the world to see the matter, and who would blame them. They are now in new unprecedented situation of supporting three versions of the OS, which is at least one over where they’d like to be in 2010.

The problem is that with an important deadline for XP SP2 nearing on 13 July, users continue to cling stubbornly to XP in whatever form they can. Its death has been foretold but it just won’t die.

According to security service provider Qualys, with that deadline approaching, a third of business PCs still run SP2 and need to move to SP3 to maintain support. That is an amazing stat. The operating system is in its tenth year and still large numbers of businesses stick by a service pack that became obsolete over two years ago.

At this rate of adoption,  even getting to Windows XP SP3 will take at least another year, perhaps longer when point of sale terminals are taken into account (anecdotally, some of these still run the embedded version of Windows 2000). And SP3 is no great fix as it takes Microsoft’s support cycle to April 2014, which conceivably means that XP could be hanging around for at least a year or two after that.

Even if Qualys’s estimates of XP’s grip on the business market are pessimistically high at 80 percent (and they ignore the lesser problem in the consumer space where service packs arrive unbidden), by the middle of the current decade, corners of the business world will be running parts of their businesses on a code base a decade and a half old.

The concern, of course, is security although that presumes that newer software is less vulnerable which is not always the case.

If we assume that the standalone OS model we have grown used to is on its last legs, this suggests that Vista and Windows 7 could hang around as long as XP has managed to, fuelled by the need to keep legacy hardware going.  By that calculation, Windows 7 could conceivably be hiding away on some PCs as far out as 2025.

Microsoft might now have a smaller market cap than Apple but you can see why it still a more profitable enterprise. People choose Apple but people need Microsoft.