XML Parsing Error: no element found

My website was running perfectly without errors both on IIS and VS2013. Now today it stopped working in IIS 7 but working on VS2013. when i explore it using localhost/bsd then it gave this error :

XML Parsing Error: no element found Location: http://localhost/BSD/Builder.aspx Line Number 1, Column 1:

This error goes same for all page while accessing from IIS Localhost

As you can see in picture , I surfed internet and found these two :

http://forums.asp.net/t/1004395.aspx?What+causes+this+XML+Parsing+Error+no+element+found

http://www.c-sharpcorner.com/Forums/Thread/216997/how-to-resolve-xml-parsing-error-no-element-found.aspx

but none of them helped me.