http://support.dell.com /support/edocs/systems /ins1545/en/SM/index.htm\
remove the spaces from the above link before copy paste to browser window.
the insulator is missing? Look in the service manual, no not the motherboard, may be a factory defect.
fould the problem to be the keyboard.
My friend has a Dell laptop so stole the board from his and voila...it works fine.