Sometimes it’s hard to let go of a good thing. For many users, Windows XP has been just that. The durable operating system has had a particularly long run, making its debut in 2001. In computing time, though, 10 years is an eternity, and Microsoft is now nudging users toward upgrading to the more advanced — and more secure  — Windows 7 OS.
Despite the bells and whistles of newer desktop OSs, many users still rely on older versions. According to data from Net Applications, Hot Hardware  found that Windows XP is still the OS to beat, maintaining a 46 percent share of the desktop market as of April 2012.
As for the remaining desktop OS users, the market breaks down like this:
Microsoft has already warned users that official support for Windows XP  will come to an end on April 8, 2014. Because the average enterprise deployment can take from 18 to 32 months, the company says, businesses that haven’t yet upgraded to Windows 7 would be wise to make the move now.
While the pain of migrating legacy enterprise applications is often cited as a reason to delay an enterprisewide OS upgrade, it might be more painful to have an out-of-support OS running in the enterprise network.