Unable to add new items in VS2012 solution

I am unable to add new items to my solutions using VS2012. 

Everytime i click Add -> New Item there is no dialog box opening.

If i use Add -> Class , i am presented with a messagebox stating that: 

Set property 'System.Windows.Resourcedictionary.Deferrablecontent' threw an exception.

I get a similar message if i try to add a reference to my solution.