A certified class action lawsuit has been filed against the computer company regarding certain Pavilion models of notebook computers. The class action claims the computers contain defective inverters. An inverter is the component that regulates voltage to light the display screen. When an inverter fails, the screen becomes extremely dim or flickers, rendering the computer useless. An inverter costs less than $20, but Hewlett-Packard allegedly quoted consumers $650 to fix the problem. The lawsuit also claims Hewlett-Packard knew about the defect before it sold the computers to the public.