Fixed:- IE-10 UpdatePanel PostBack Issue with ASP.Net Framework 4.0
IE10 has a new user agent which requires an update of your ASP.NET browser definition files.
As IE10 is a new browser so it has new browser definition which was not included in .Net Framework 4.0.
Resolution:- Install Hotfix for the same from here :-
http://support.microsoft.com/kb/2600088