When Windows XP support ends,nothing will happen.Microsoft simply won't make any new updates for it anymore and you will have no support for it from Microsoft anymore also.
Many people will simply continue to use it anyway for the next many years.At least I will...at least until 2020.
The problem is that many people stop using an OS just because Microsoft does not support it anymore.(I will never understand that).
But that's not the case with me.As long as everything I do works like a charm on Windows XP then I really see NO REASON to spend money AND time upgrading an operating system just because Microsoft does not support it anymore.Who cares about that lol...I never needed their support anyway.
I mainly use computers for programming and I am STILL using old Visual Studio 2002 (7.0) which can even be installed and used on older Windows 2000.And Windows XP supports Visual Studio versions all up to 2010 (10.0).So by the time I EVEN update Visual Studio from 2002 (7.0) to Visual Studio 2010 (10.0),it will be probably 2020. or 2025. lol.I don't care for instance if Visual Studio 2012 (11.0) is not supported on Windows XP since I have MANY versions of Visual Studio I can update to BEFORE Visual Studio 2012 (11.0).
Besides...I don't like that new .NET framework 4.5 since applications made in it work only in Windows 7 or later.And that's just stupid since MANY people who will buy programs from me still use Windows XP and some schools use even older OS.So what should I tell them?..."To use my software,you must update OPERATING SYSTEM ONLY" lol...
That is a big cost AND time consuming.
Programs I make on Windows XP work on Windows versions starting all the way from Windows 98 first edition and later.On that way I do not need to worry wether my applications will work or not.Since once you disappoint your clients,it is a lot harder for them to come back to you.
Besides...it is a LOT cheaper for them to just pay for my software rather than paying for my software AND new operating system just so that my software can even work lol.The hell with that!
So Windows XP will still rule after april 2014.
Cheers!