problem after login in wordpress site

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http://askubuntu.com – I have installed WordPress first installation on Apache server Its opening fine but when i logged in with my user id and password http://examplesite.com/wp-login.php It is showing blank in Firefox and in IE page not open with no errors. I cleared all my browsers cache history still not able to open the page after login. There is no errors logs generated. wordpress version3.4.2 php 5.3.3 mysql 5.1.6 (HowTos)