not sure but I would count on

 - no more security updates
 - no more driver updates = no support for recent / new hardware
 - no support for recent / new software (Office 2015, Poser 2015, Vue 2015, ...)
 - no more respons from the MS Helpdesk
 - and eventually: no more MS webpages to download Service Packs, Knowledge Base patches, etc

In return, XP will be even more stable than it's now :-)

- - - - - 

Usually I'm wrong. But to be effective and efficient, I don't need to be correct or accurate.

visit www.aRtBeeWeb.nl (works) or Missing Manuals (tutorials & reviews) - both need an update though