My Compaq Presario c500 will not turn on when plugged int a/c power. The indicator lights constantly blink or flicker, If I unplug a/c and install a charged battery the indicator lights glow constant an the machine will boot on. If I then plug in the a/c power, the machine will function properly as long as the battery has a charge. The charge does not run down as fast when the a/c is plugged in as it does when operating on battery alone. I have changed the hard drive, ram and power jack, checked for driver updates and current BIOS all to no avail. Short of trashing the motherboard, is there anything else I can do to try to resolve this problem? I have heard o several otters having the same problem wit their C500 and one person with the same or a similar problem with a Toshiba L305.