Site is working fine on all browsers but why not on IE?

[DR Tech]

IE actually does not follow the W3C standard, which is why most web developers in the world gave up on IE. If you go to a few sites - you will even see a warning saying this website is best viewed with alternative browsers. Problem is Microsoft is a sad little cry baby and angry no one listening to them and their standards.
But the latest version of IE

if you want to see how good a browser is to the latest standards you can do the acid 3 test.
http://acid3.acidtests.org/

Just open that link with any browser - and it will score that browser on how will it supports modern day standards. Anything less then 100 - its not worth supporting.